Inverse matrix introduction

WEBVTT
Kind: captions
Language: en

00:00:01.060 --> 00:00:02.730
- [Instructor] We know that
when we're just multiplying

00:00:02.730 --> 00:00:05.780
regular numbers we have
the notion of a reciprocal.

00:00:05.780 --> 00:00:08.640
For example, if I were to take
two and I were to multiply it

00:00:08.640 --> 00:00:12.270
by its reciprocal, it
would be equal to one.

00:00:12.270 --> 00:00:13.640
Or if I were to just take a

00:00:13.640 --> 00:00:16.020
and a is not equal to zero
and I were to multiply it

00:00:16.020 --> 00:00:19.800
by its reciprocal for any
a, that is not equal to zero

00:00:19.800 --> 00:00:21.950
this will also be equal to one.

00:00:21.950 --> 00:00:25.700
And this is a number that
if I multiply times anything

00:00:25.700 --> 00:00:29.040
I am just going to get
that original number.

00:00:29.040 --> 00:00:31.220
So that's interesting, put
in the back of our minds

00:00:31.220 --> 00:00:33.290
you learned this many, many years ago.

00:00:33.290 --> 00:00:34.500
Now we also have something

00:00:34.500 --> 00:00:37.040
that comes out of our
knowledge of functions.

00:00:37.040 --> 00:00:39.900
We know that if there's some function

00:00:39.900 --> 00:00:44.030
let's call it f(x) that
goes from some set,

00:00:44.030 --> 00:00:45.790
we call that our domain

00:00:45.790 --> 00:00:49.290
to some other set we call that our range,

00:00:49.290 --> 00:00:51.070
that in many cases, not all cases

00:00:51.070 --> 00:00:55.117
so this is the function f
that goes from x to f(x).

00:00:56.060 --> 00:00:59.500
That in many cases,
but not always the case

00:00:59.500 --> 00:01:02.200
there's another function
that can take us back.

00:01:02.200 --> 00:01:06.270
And we call that other
function, the inverse of f.

00:01:06.270 --> 00:01:11.080
So that if you apply
the inverse of f to f(x)

00:01:11.080 --> 00:01:13.130
you're going to get
back to where you were.

00:01:13.130 --> 00:01:15.240
You're going to get back to x.

00:01:15.240 --> 00:01:17.180
And we also know that it
goes the other way around.

00:01:17.180 --> 00:01:21.173
For example, if you did
f of f inverse of x,

00:01:24.260 --> 00:01:26.800
that too will get us back to x.

00:01:26.800 --> 00:01:28.230
So the natural question is

00:01:28.230 --> 00:01:31.240
is there an analog for
an inverse of a function,

00:01:31.240 --> 00:01:33.410
or for reciprocal when we're multiplying

00:01:33.410 --> 00:01:36.333
when we think about matrices.

00:01:37.450 --> 00:01:40.090
So let's play with a few ideas.

00:01:40.090 --> 00:01:43.310
So let's imagine a matrix
as a transformation,

00:01:43.310 --> 00:01:45.330
which we have already talked about it.

00:01:45.330 --> 00:01:47.560
When we think about
matrices as transformations

00:01:47.560 --> 00:01:49.020
they really are functions.

00:01:49.020 --> 00:01:51.190
There are functions that
are taking one point

00:01:51.190 --> 00:01:52.600
in a certain dimensional space

00:01:52.600 --> 00:01:55.590
let's say in the coordinate
plane, to another point

00:01:55.590 --> 00:01:58.250
it transforms a vector to another vector.

00:01:58.250 --> 00:02:01.920
For example, let's imagine
something that does

00:02:01.920 --> 00:02:06.160
a clockwise 90 degree rotation.

00:02:06.160 --> 00:02:08.990
And we know how to construct
that transformation matrix

00:02:08.990 --> 00:02:11.130
which really is a function.

00:02:11.130 --> 00:02:14.070
What it does is, in our
transformation matrix

00:02:14.070 --> 00:02:19.070
we want to say, what do we do
with the one zero unit vector?

00:02:20.760 --> 00:02:25.700
And what also do we do with
the zero one unit vector

00:02:25.700 --> 00:02:27.700
when you do that transformation?

00:02:27.700 --> 00:02:32.330
Well, if you're doing a
90 degree clockwise turn,

00:02:32.330 --> 00:02:34.530
then the one zero unit vector

00:02:34.530 --> 00:02:37.520
is going to go right over here.

00:02:37.520 --> 00:02:39.000
And so that's going to be turned

00:02:39.000 --> 00:02:42.280
into the zero negative one vector.

00:02:42.280 --> 00:02:43.990
So I'll write that right there.

00:02:43.990 --> 00:02:46.980
And then the zero one
vector is going to be turned

00:02:46.980 --> 00:02:49.400
into the one zero vector.

00:02:49.400 --> 00:02:50.233
So let me write it down.

00:02:50.233 --> 00:02:53.000
This is 90 degrees clockwise

00:02:54.010 --> 00:02:54.900
and then we can think about

00:02:54.900 --> 00:02:57.340
what 90 degree counter-clockwise

00:03:01.290 --> 00:03:02.760
would look like

00:03:02.760 --> 00:03:04.010
you're going counterclockwise

00:03:04.010 --> 00:03:06.940
your original one zero
vector right over here

00:03:06.940 --> 00:03:07.950
is going to go over here.

00:03:07.950 --> 00:03:10.940
It's going to become the zero one vector.

00:03:10.940 --> 00:03:13.400
So we will write that right over here.

00:03:13.400 --> 00:03:18.400
And then the zero one vector
will then become this vector

00:03:18.410 --> 00:03:20.840
if you're doing a 90 degree
counterclockwise rotation

00:03:20.840 --> 00:03:24.400
it's going to become the
negative one zero vector

00:03:24.400 --> 00:03:26.400
negative one, zero vector.

00:03:26.400 --> 00:03:29.150
So in theory these two transformations

00:03:29.150 --> 00:03:30.830
should undo each other.

00:03:30.830 --> 00:03:31.990
If I do a transformation

00:03:31.990 --> 00:03:33.910
that first gets 90 degrees clockwise,

00:03:33.910 --> 00:03:35.170
and then I apply a transformation

00:03:35.170 --> 00:03:36.930
that's 90 degrees counter-clockwise

00:03:36.930 --> 00:03:39.630
I should get back to where we began.

00:03:39.630 --> 00:03:40.630
Now let's see what happens

00:03:40.630 --> 00:03:43.600
when we compose these two transformations

00:03:43.600 --> 00:03:44.810
and we know how to do that.

00:03:44.810 --> 00:03:45.660
We've already talked about it.

00:03:45.660 --> 00:03:49.510
We essentially multiply
these two matrices.

00:03:49.510 --> 00:03:53.040
If you were to multiply
zero, negative one,

00:03:53.040 --> 00:03:58.040
one, zero times zero,
negative one, one, zero.

00:03:58.950 --> 00:03:59.793
What do we get?

00:04:00.850 --> 00:04:03.930
Well, let's see these, this top left

00:04:03.930 --> 00:04:05.550
this is composing two, two

00:04:05.550 --> 00:04:08.570
by two matrices is equivalent
to multiplying them

00:04:08.570 --> 00:04:09.910
we've seen that in other videos.

00:04:09.910 --> 00:04:13.590
And so first we will look
at this row and this column

00:04:13.590 --> 00:04:17.640
and that's going to be zero
times zero plus one times one.

00:04:17.640 --> 00:04:19.050
So that is going to be one.

00:04:19.050 --> 00:04:22.370
They're going to look at
this row and this column.

00:04:22.370 --> 00:04:24.500
So zero times negative one

00:04:24.500 --> 00:04:27.350
plus one times zero is
just going to be zero.

00:04:27.350 --> 00:04:29.850
And then we're going to multiply

00:04:29.850 --> 00:04:31.610
this row times each of those columns.

00:04:31.610 --> 00:04:34.530
So negative one times zero is zero

00:04:34.530 --> 00:04:37.220
plus zero times one is zero

00:04:37.220 --> 00:04:40.710
and then negative one
times negative one is one

00:04:40.710 --> 00:04:43.040
plus zero times zero is one.

00:04:43.040 --> 00:04:46.970
And look what happened when
we took the composition of

00:04:46.970 --> 00:04:50.170
these two matrices that
should undo each other

00:04:50.170 --> 00:04:51.200
we see that it does.

00:04:51.200 --> 00:04:53.900
It turns into the identity transformation

00:04:53.900 --> 00:04:55.180
or the identity matrix.

00:04:55.180 --> 00:04:57.890
We know that this matrix right
over here as a transformation

00:04:57.890 --> 00:05:01.370
it's just going to map
everything onto themselves.

00:05:01.370 --> 00:05:03.850
Now, this is really
interesting because if we view

00:05:03.850 --> 00:05:06.900
these two by two transformation
matrices as functions,

00:05:06.900 --> 00:05:09.870
we've just shown that if we call this

00:05:09.870 --> 00:05:13.930
say our first function then
can call this it's inverse.

00:05:13.930 --> 00:05:16.460
And actually we use that same language

00:05:16.460 --> 00:05:18.410
when we talk about matrices.

00:05:18.410 --> 00:05:21.330
If we call this as being equal to A

00:05:21.330 --> 00:05:24.730
we would call this as
being equal to A inverse.

00:05:24.730 --> 00:05:27.400
So if I were to take matrix A

00:05:27.400 --> 00:05:30.630
and I were to multiply
that times its inverse

00:05:30.630 --> 00:05:35.120
I should get the identity
matrix, which is right over here.

00:05:35.120 --> 00:05:36.730
And here I'm speaking in generalities

00:05:36.730 --> 00:05:38.820
I'm not even just talking
about the two by two case.

00:05:38.820 --> 00:05:40.160
That should be the three by three case

00:05:40.160 --> 00:05:42.800
the four by four case so on and so forth.

00:05:42.800 --> 00:05:45.610
And we also know, that I could
have defined this bottom one

00:05:45.610 --> 00:05:48.180
as A and the top one as A inverse.

00:05:48.180 --> 00:05:50.370
And so the other way
should be true as well.

00:05:50.370 --> 00:05:54.180
A inverse times A should
also be equivalent

00:05:54.180 --> 00:05:55.420
to the identity matrix.

00:05:55.420 --> 00:05:58.080
And so that's completely
analogous to what we saw

00:05:58.080 --> 00:05:59.600
in these function examples

00:05:59.600 --> 00:06:01.210
between a function and its inverse

00:06:01.210 --> 00:06:02.820
because the other day, as we said

00:06:02.820 --> 00:06:05.020
an end by end matrix can be viewed

00:06:05.020 --> 00:06:09.490
as a transformation can
be viewed as a function.

00:06:09.490 --> 00:06:11.740
And we also see that it
has analogs to just how

00:06:11.740 --> 00:06:13.320
we think about multiplication.

00:06:13.320 --> 00:06:15.300
'Cause here we could
do this multiplication

00:06:15.300 --> 00:06:18.040
as a composition of transformations

00:06:18.040 --> 00:06:21.230
but we also can just view
this as matrix multiplication.

00:06:21.230 --> 00:06:22.510
And so if we take a matrix

00:06:22.510 --> 00:06:24.760
and we multiply it by its inverse,

00:06:24.760 --> 00:06:26.360
that's analogous to taking a number

00:06:26.360 --> 00:06:28.220
and multiplying by its reciprocal

00:06:28.220 --> 00:06:30.030
and we get the equivalent of

00:06:30.030 --> 00:06:31.900
what in the number
world would just be one,

00:06:31.900 --> 00:06:34.320
but in the matrix world
is the identity matrix.

00:06:34.320 --> 00:06:36.670
'Cause the identity matrix
has this nice property

00:06:36.670 --> 00:06:39.960
that if I were to take the identity matrix

00:06:39.960 --> 00:06:42.690
and I were to multiply at times any matrix

00:06:42.690 --> 00:06:44.810
you're gonna get the original matrix again

00:06:44.810 --> 00:06:48.080
which is what we saw at least
within the analog that we saw

00:06:48.080 --> 00:06:49.953
in the regular number world.


Help Khan Academy Double Down On Our Efforts

WEBVTT
Kind: captions
Language: en

00:00:00.350 --> 00:00:02.910
- Hi everyone, Sal Khan
here from Khan Academy

00:00:02.910 --> 00:00:04.330
and I just wanted to remind you

00:00:04.330 --> 00:00:06.550
that if you're in the position to do so,

00:00:06.550 --> 00:00:08.900
to think about making a
donation to Khan Academy.

00:00:08.900 --> 00:00:10.800
We are a not for profit organization

00:00:10.800 --> 00:00:12.810
and we can only exist through donations

00:00:12.810 --> 00:00:14.710
from folks like yourself.

00:00:14.710 --> 00:00:16.289
And now, as we are approaching

00:00:16.289 --> 00:00:20.320
the one year anniversary of
schools in the United States

00:00:20.320 --> 00:00:21.960
and actually schools in much of the world

00:00:21.960 --> 00:00:25.120
having to shut down physically
because of the pandemic,

00:00:25.120 --> 00:00:27.850
it's even more that we
double down our efforts.

00:00:27.850 --> 00:00:30.080
Obviously, during the school closures,

00:00:30.080 --> 00:00:33.800
many, many, many folks leaned
even more on Khan Academy.

00:00:33.800 --> 00:00:35.500
It was the place where they went

00:00:35.500 --> 00:00:38.120
to make sure that they kept
pace with their classes

00:00:38.120 --> 00:00:39.600
or if they weren't
getting distance learning

00:00:39.600 --> 00:00:41.520
that they were able to get their learning.

00:00:41.520 --> 00:00:42.670
But now, as we're starting to see

00:00:42.670 --> 00:00:43.980
the light at the end of the tunnel,

00:00:43.980 --> 00:00:45.720
I've talked about this very publicly,

00:00:45.720 --> 00:00:49.070
we really have to view this
as a disaster recovery effort

00:00:49.070 --> 00:00:52.290
because so many students,
most students arguably,

00:00:52.290 --> 00:00:54.470
have accumulated all
sorts of learning loss

00:00:54.470 --> 00:00:55.800
over this past year.

00:00:55.800 --> 00:00:58.140
Some students have fallen
off the radar completely.

00:00:58.140 --> 00:01:01.240
And so, as we go into the
end of this school year

00:01:01.240 --> 00:01:03.280
and actually the next several years,

00:01:03.280 --> 00:01:06.770
we need to make sure that there
is free accessible resources

00:01:06.770 --> 00:01:08.560
for students, for parents,

00:01:08.560 --> 00:01:10.248
and for teachers and school districts

00:01:10.248 --> 00:01:12.850
to make sure they can personalize

00:01:12.850 --> 00:01:14.090
to the needs of students.

00:01:14.090 --> 00:01:15.760
And as you can imagine, that's exactly

00:01:15.760 --> 00:01:17.800
what Khan Academy is focused on.

00:01:17.800 --> 00:01:20.760
We had over 12 billion learning minutes

00:01:20.760 --> 00:01:23.840
on Khan Academy in
2020, and we expect that

00:01:23.840 --> 00:01:25.860
that will only accelerate
in the years ahead.

00:01:25.860 --> 00:01:27.440
That's 12 billion minutes

00:01:27.440 --> 00:01:29.129
of learners around the world

00:01:29.129 --> 00:01:32.350
really being able to
dig in into their gaps,

00:01:32.350 --> 00:01:34.200
make up for any unfinished learning,

00:01:34.200 --> 00:01:37.090
and then learn at grade level or beyond.

00:01:37.090 --> 00:01:38.580
So if you're in a position to do so,

00:01:38.580 --> 00:01:40.970
the social return on investment,

00:01:40.970 --> 00:01:42.910
the social benefit to cost ratio

00:01:42.910 --> 00:01:45.590
for Khan Academy is off the charts.

00:01:45.590 --> 00:01:48.528
And so hopefully, we'll
make both your heart

00:01:48.528 --> 00:01:50.960
and your head feel good about the impact

00:01:50.960 --> 00:01:52.500
that you will have on millions

00:01:52.500 --> 00:01:53.960
and millions of learners today

00:01:53.960 --> 00:01:56.353
and billions of learners in the future.


Proof: Matrix determinant gives area of image of unit square under mapping

WEBVTT
Kind: captions
Language: en

00:00:00.480 --> 00:00:02.370
- [Instructor] The goal of
this video is to feel good

00:00:02.370 --> 00:00:04.920
about the connection
that we've talked about

00:00:04.920 --> 00:00:07.200
between the absolute
value of the determinant

00:00:07.200 --> 00:00:08.780
of a two by two matrix

00:00:08.780 --> 00:00:12.720
and the area of the
parallelogram that's defined

00:00:12.720 --> 00:00:15.790
by the two column vectors of that matrix.

00:00:15.790 --> 00:00:18.160
So for example, I have this column vector

00:00:18.160 --> 00:00:21.720
right over here ac, so
that's this blue vector.

00:00:21.720 --> 00:00:23.070
So this distance right over here,

00:00:23.070 --> 00:00:25.230
it goes a in the x direction.

00:00:25.230 --> 00:00:27.900
So this distance right over here is a,

00:00:27.900 --> 00:00:30.070
and then it goes c in the y direction.

00:00:30.070 --> 00:00:33.930
So this distance right
over here is equal to c.

00:00:33.930 --> 00:00:38.930
And so this distance up
here is also equal to a,

00:00:39.040 --> 00:00:42.880
and this is also equal to c.

00:00:42.880 --> 00:00:44.550
So we have this vector

00:00:44.550 --> 00:00:46.910
and then we have the bd vector,

00:00:46.910 --> 00:00:49.640
and bd vector, so in the x direction

00:00:49.640 --> 00:00:53.050
it goes a distance of b right over there.

00:00:53.050 --> 00:00:55.830
Or if we draw it over here,
it goes a distance of b.

00:00:55.830 --> 00:00:57.030
And in the vertical direction,

00:00:57.030 --> 00:00:59.540
again it goes a distance of d.

00:00:59.540 --> 00:01:01.500
So this right over here is d

00:01:01.500 --> 00:01:04.540
and this distance right over here is d.

00:01:04.540 --> 00:01:07.930
And we can see that the
parallelogram created or defined

00:01:07.930 --> 00:01:12.930
by those two vectors, it's
area is right over there.

00:01:13.500 --> 00:01:17.440
Now let's see if we can
connect that to the determinant

00:01:17.440 --> 00:01:20.160
or the absolute value of the
determinant of this matrix.

00:01:20.160 --> 00:01:23.040
And we're just going to assume
for the sake of simplicity

00:01:23.040 --> 00:01:26.080
that a, b, c and d are positive values,

00:01:26.080 --> 00:01:29.060
although we can in the
future do this same thing

00:01:29.060 --> 00:01:30.470
where we had some other combination

00:01:30.470 --> 00:01:32.250
where some of them are not positive,

00:01:32.250 --> 00:01:33.395
but this will hopefully give you a clue

00:01:33.395 --> 00:01:35.505
of how we can prove it.

00:01:35.505 --> 00:01:40.505
Now, how can we figure out the
area of this parallelogram?

00:01:40.700 --> 00:01:43.260
Well, one technique would be find the area

00:01:43.260 --> 00:01:47.530
of this larger rectangle right over here,

00:01:47.530 --> 00:01:48.900
and then from that,

00:01:48.900 --> 00:01:52.740
subtract out the parts that
are not in the parallelogram.

00:01:52.740 --> 00:01:54.350
And so let's do that.

00:01:54.350 --> 00:01:57.163
So what's the area of
this larger rectangle?

00:01:58.010 --> 00:02:00.010
Let's see the dimensions here are,

00:02:00.010 --> 00:02:04.020
this length from here to here is a,

00:02:04.020 --> 00:02:07.210
and then from here to here is b.

00:02:07.210 --> 00:02:09.380
So this is a plus b on this side.

00:02:09.380 --> 00:02:11.320
And on this side up here,

00:02:11.320 --> 00:02:15.020
this part is d and then this
part is c right over here.

00:02:15.020 --> 00:02:16.120
So it's d plus c.

00:02:16.120 --> 00:02:17.910
So the area of the whole thing

00:02:17.910 --> 00:02:22.910
is going to be a plus b, times d plus c,

00:02:23.600 --> 00:02:25.350
which is equal to, we just do

00:02:25.350 --> 00:02:27.070
the distributive property a few times.

00:02:27.070 --> 00:02:32.070
It's going to be ad
plus ac plus bd plus bc.

00:02:35.530 --> 00:02:37.760
Now, from that we're going
to wanna subtract out all

00:02:37.760 --> 00:02:40.430
of these other parts that
are not in the parallelogram.

00:02:40.430 --> 00:02:41.570
So let's do that.

00:02:41.570 --> 00:02:44.310
So you have this triangle right over here

00:02:44.310 --> 00:02:48.160
whose area would be ac over
two, a times c over two,

00:02:48.160 --> 00:02:50.920
but you also have this one,
which has the same area.

00:02:50.920 --> 00:02:52.680
So if we subtract both of them out

00:02:52.680 --> 00:02:54.950
we'd wanna subtract out a total of ac.

00:02:54.950 --> 00:02:56.800
Each of those are ac over two.

00:02:56.800 --> 00:03:00.200
So to count both of them
let's subtract out an ac.

00:03:00.200 --> 00:03:03.470
And then of course we could
do these two triangles.

00:03:03.470 --> 00:03:06.850
And the area of each of these
triangles is bd over two,

00:03:06.850 --> 00:03:08.670
b times d over two,

00:03:08.670 --> 00:03:11.100
but add them together,
their combined area is bd.

00:03:11.100 --> 00:03:12.953
So let's subtract that out, minus bd.

00:03:13.900 --> 00:03:18.210
And now, what is the area
of this right over here?

00:03:18.210 --> 00:03:22.910
Well, that is b times
c, so minus b times c,

00:03:22.910 --> 00:03:25.650
actually and that's also the
area of this right over here.

00:03:25.650 --> 00:03:27.030
So we have another b times c,

00:03:27.030 --> 00:03:29.980
so minus 2bc.

00:03:29.980 --> 00:03:31.780
So let's see what's going on.

00:03:31.780 --> 00:03:35.740
So if we subtract these
out, that takes out that,

00:03:35.740 --> 00:03:40.110
that takes out that, and
if you take bc minus 2bc

00:03:40.110 --> 00:03:42.650
we're gonna be left
with just a negative bc.

00:03:42.650 --> 00:03:44.280
So all of this is going to be equal

00:03:44.280 --> 00:03:46.900
to ad, what we have there.

00:03:46.900 --> 00:03:50.860
Bc minus 2bc is just
gonna be a negativebc.

00:03:50.860 --> 00:03:53.843
Well, this is going to be the determinant

00:03:53.843 --> 00:03:58.843
of our matrix, a times d minus b times c.

00:03:59.550 --> 00:04:02.280
So this isn't a proof that
for any a, b, c, or d,

00:04:02.280 --> 00:04:04.430
the absolute value of
the determinant is equal

00:04:04.430 --> 00:04:06.500
to this area, but it
shows you the case where

00:04:06.500 --> 00:04:07.830
you have a positive determinant

00:04:07.830 --> 00:04:09.830
and all of these values are positive.

00:04:09.830 --> 00:04:11.620
So hopefully that feels
somewhat satisfying.

00:04:11.620 --> 00:04:13.720
And you can try, if you
like to prove the cases

00:04:13.720 --> 00:04:15.470
if you don't have a positive determinant

00:04:15.470 --> 00:04:18.003
or if some combination
of these are negative.


Finding area of figure after transformation using determinant

WEBVTT
Kind: captions
Language: en

00:00:00.170 --> 00:00:03.220
- [Tutor] We're told to consider
this matrix transformation

00:00:03.220 --> 00:00:04.710
or this is a matrix that you can view,

00:00:04.710 --> 00:00:06.190
represents a transformation

00:00:06.190 --> 00:00:07.810
on the entire coordinate plane.

00:00:07.810 --> 00:00:10.740
And then they tell us that the
transformation is performed

00:00:10.740 --> 00:00:12.310
on the following rectangle.

00:00:12.310 --> 00:00:15.470
So this is the rectangle
before the transformation

00:00:15.470 --> 00:00:17.390
and they say, what is the area

00:00:17.390 --> 00:00:21.530
of the image of the rectangle
under this transformation?

00:00:21.530 --> 00:00:25.210
So the image of the rectangle
is what the rectangle becomes

00:00:25.210 --> 00:00:26.460
after the transformation.

00:00:26.460 --> 00:00:28.240
So pause this video and
see if you can answer that

00:00:28.240 --> 00:00:30.090
before we work through it on our own.

00:00:31.490 --> 00:00:34.260
All right, so the main
thing to realize is,

00:00:34.260 --> 00:00:36.640
if we have a matrix transformation

00:00:36.640 --> 00:00:38.990
or a transformation matrix like this

00:00:38.990 --> 00:00:42.810
if we take the absolute
value of its determinant,

00:00:42.810 --> 00:00:47.810
that value tells us how much
that transformation scales up

00:00:49.350 --> 00:00:51.200
areas of figures.

00:00:51.200 --> 00:00:52.160
So let's just do that,

00:00:52.160 --> 00:00:55.320
let's evaluate the absolute
value of the determinant here.

00:00:55.320 --> 00:00:57.960
So the absolute value of the determinant

00:00:57.960 --> 00:01:00.880
would be the absolute value of 5 times 8,

00:01:00.880 --> 00:01:05.880
5 times 8 minus 9 times 4, 9 times 4.

00:01:07.290 --> 00:01:09.240
Remember for a 2 by 2 matrix,

00:01:09.240 --> 00:01:12.380
the determinant is just this times this

00:01:12.380 --> 00:01:15.310
minus this times that.

00:01:15.310 --> 00:01:20.310
And so that's going to be the
absolute value of 40 minus 36

00:01:20.860 --> 00:01:23.090
which is just the absolute value of 4

00:01:23.090 --> 00:01:25.620
which is just going to be equal to 4.

00:01:25.620 --> 00:01:28.280
So this tells us that this transformation

00:01:28.280 --> 00:01:32.400
will scale up area by a factor of 4.

00:01:32.400 --> 00:01:35.120
So what's the area before
the transformation?

00:01:35.120 --> 00:01:37.660
Well, we can see that this is, let's see,

00:01:37.660 --> 00:01:42.660
it's 5 units tall and it is 7 units wide.

00:01:43.700 --> 00:01:48.320
So this has an area of 35 square
units, pre transformation.

00:01:48.320 --> 00:01:50.650
So post transformation,
we just multiply it

00:01:50.650 --> 00:01:53.520
by the absolute value of
the determinant to get,

00:01:53.520 --> 00:01:57.710
let's see, 4 times 30 is 120

00:01:57.710 --> 00:01:59.990
plus 4 times 5 is another 20.

00:01:59.990 --> 00:02:01.210
So this is going to get us

00:02:01.210 --> 00:02:05.693
to 140 square units and we're done.


Interpreting determinants in terms of area

WEBVTT
Kind: captions
Language: en

00:00:00.390 --> 00:00:02.810
- [Instructor] So I have
a two by two matrix here

00:00:02.810 --> 00:00:06.480
and we could view it as
having two column vectors.

00:00:06.480 --> 00:00:09.980
So the first column can
define this vector three, one,

00:00:09.980 --> 00:00:11.620
which I've depicted in blue here.

00:00:11.620 --> 00:00:14.792
And then that second
column, you can view it

00:00:14.792 --> 00:00:16.930
as telling us that we have
another vector, one, two,

00:00:16.930 --> 00:00:19.780
which I have depicted in this pink color.

00:00:19.780 --> 00:00:22.494
Now, an interesting
interpretation of the determinant

00:00:22.494 --> 00:00:24.970
of this two by two matrix is that

00:00:24.970 --> 00:00:26.980
the absolute value of the determinant

00:00:26.980 --> 00:00:29.272
is the area of the parallelogram defined

00:00:29.272 --> 00:00:31.220
by these two vectors.

00:00:31.220 --> 00:00:33.100
What I mean by the parallelogram defined

00:00:33.100 --> 00:00:34.660
by these two vectors?

00:00:34.660 --> 00:00:37.590
Well, imagine taking this
bottom vector and shifting it

00:00:37.590 --> 00:00:40.546
so it's tail is at the
head of this pink vector.

00:00:40.546 --> 00:00:44.650
So it would look like this, hand draw it.

00:00:44.650 --> 00:00:46.460
Looks something like that.

00:00:46.460 --> 00:00:48.690
And then if you were to
take this pink vector

00:00:48.690 --> 00:00:51.540
and copy it and shift
it up into the right.

00:00:51.540 --> 00:00:54.432
So its tail is at the head
of the original blue vector.

00:00:54.432 --> 00:00:56.930
It's going to look something like that.

00:00:56.930 --> 00:00:59.040
And so you can see, you
can use that technique

00:00:59.040 --> 00:01:02.160
to take any two vectors
in the coordinate plane.

00:01:02.160 --> 00:01:04.660
And they will define a parallelogram.

00:01:04.660 --> 00:01:06.120
And it turns out that the area

00:01:06.120 --> 00:01:08.230
of this parallelogram is going to be equal

00:01:08.230 --> 00:01:10.830
to the absolute value of the determinant

00:01:10.830 --> 00:01:12.080
of this matrix here.

00:01:12.080 --> 00:01:13.510
So what's that going to be?

00:01:13.510 --> 00:01:15.420
Well, we know of figure
out the determinant.

00:01:15.420 --> 00:01:18.250
It is three times two, which is six.

00:01:18.250 --> 00:01:23.070
Minus one times one, which is
one, which is equal to five.

00:01:23.070 --> 00:01:26.000
And of course the absolute
value of five is five.

00:01:26.000 --> 00:01:28.240
Now that's pretty cool in and of itself.

00:01:28.240 --> 00:01:31.450
We figured out one
interpretation of a determinant

00:01:31.450 --> 00:01:33.180
which will be useful as we build up

00:01:33.180 --> 00:01:35.320
our understanding of matrices.

00:01:35.320 --> 00:01:37.781
But another interpretation
is to say, all right,

00:01:37.781 --> 00:01:41.310
what if A is a transformation matrix,

00:01:41.310 --> 00:01:42.890
and I'm just rewriting it.

00:01:42.890 --> 00:01:45.420
So we know what a
transformation matrix does.

00:01:45.420 --> 00:01:49.350
It tells us what to do with
the unit vectors, so to speak.

00:01:49.350 --> 00:01:52.800
So for example, I have
this vector right over here

00:01:52.800 --> 00:01:56.100
which is the vector one, zero.

00:01:56.100 --> 00:01:58.780
We know that a transformation
matrix says, all right

00:01:58.780 --> 00:02:00.230
take that one, zero vector

00:02:00.230 --> 00:02:03.220
and turn it into the three, one vector.

00:02:03.220 --> 00:02:06.166
So turn that into that right over there.

00:02:06.166 --> 00:02:10.260
And we know we have the
other, or another unit vector.

00:02:10.260 --> 00:02:13.040
Let's call this, this right over here

00:02:13.040 --> 00:02:16.310
is the zero, one vector.

00:02:16.310 --> 00:02:19.540
Goes zero in the X direction,
one in the Y direction.

00:02:19.540 --> 00:02:21.210
And the transformation matrix says,

00:02:21.210 --> 00:02:24.333
hey, turn that into the one, two vector.

00:02:25.520 --> 00:02:26.600
But then you can think about it,

00:02:26.600 --> 00:02:30.940
it's also not just transforming
the individual vectors.

00:02:30.940 --> 00:02:35.150
It's also scaling up the
area defined by the vectors.

00:02:35.150 --> 00:02:37.610
So the area defined by these two original,

00:02:37.610 --> 00:02:40.650
we could say unit vectors,
we can see it's one by one.

00:02:40.650 --> 00:02:42.670
It's that area right over there.

00:02:42.670 --> 00:02:44.580
So this transformation is taking us

00:02:44.580 --> 00:02:47.350
from an area of one to an area, five.

00:02:47.350 --> 00:02:49.840
It's scaling it up by a factor of five.

00:02:49.840 --> 00:02:51.470
Now that's reasonably interesting

00:02:51.470 --> 00:02:54.110
just for this one unit square.

00:02:54.110 --> 00:02:56.120
But because of that
it'll actually scale up

00:02:56.120 --> 00:02:58.690
the area of any figure.

00:02:58.690 --> 00:03:00.000
Let's say had a figure like this.

00:03:00.000 --> 00:03:04.480
So this type of oval circle
thing, it has some area.

00:03:04.480 --> 00:03:06.515
If you apply this transformation matrix

00:03:06.515 --> 00:03:09.050
it will look something like this.

00:03:09.050 --> 00:03:10.590
I'm just approximating it.

00:03:10.590 --> 00:03:13.160
It would look something like that.

00:03:13.160 --> 00:03:15.720
So this will tell us that this bigger blob

00:03:15.720 --> 00:03:19.030
has five times the area
of this original blue blob

00:03:19.030 --> 00:03:21.790
because the bigger blob is the image.

00:03:21.790 --> 00:03:24.470
Once we've transformed the smaller blob

00:03:24.470 --> 00:03:27.700
by this transformation matrix.

00:03:27.700 --> 00:03:28.810
So if I were to tell you

00:03:28.810 --> 00:03:33.413
that the area of this smaller
circle is let's say 0.6

00:03:35.700 --> 00:03:37.970
but then we were to
apply the transformation.

00:03:37.970 --> 00:03:39.370
And someone were to ask you,

00:03:40.321 --> 00:03:41.154
what is the area of this bigger blob?

00:03:41.154 --> 00:03:43.720
Which is the image of the smaller circle

00:03:43.720 --> 00:03:45.410
after the transformation?

00:03:45.410 --> 00:03:48.770
Well, you take 0.6, multiply
it by the absolute value

00:03:48.770 --> 00:03:51.210
of the determinant of the
transformation matrix.

00:03:51.210 --> 00:03:52.470
You'd multiply it by five.

00:03:52.470 --> 00:03:57.470
So 0.6 times five would
be three square units.

00:03:57.920 --> 00:04:00.060
And a hint at the reason
why this works is,

00:04:00.060 --> 00:04:02.000
is that any region on the coordinate plane

00:04:02.000 --> 00:04:05.821
can be represented as a series of squares.

00:04:05.821 --> 00:04:08.210
And then if you apply the transformation

00:04:08.210 --> 00:04:10.060
you're really just transforming each

00:04:10.060 --> 00:04:11.940
of those individual squares.

00:04:11.940 --> 00:04:15.750
So the scaling up of the area
would be the same scale you do

00:04:15.750 --> 00:04:18.133
to any one of those smaller squares.


Intro to determinant notation and computation

WEBVTT
Kind: captions
Language: en

00:00:00.420 --> 00:00:01.670
- [Instructor] In this
video, we're gonna talk

00:00:01.670 --> 00:00:05.800
about something called
determinants of matrices.

00:00:05.800 --> 00:00:08.110
So I'll start just
telling you the notation

00:00:08.110 --> 00:00:09.400
and how do you compute it.

00:00:09.400 --> 00:00:12.940
And then we'll think about
ways that you can interpret it.

00:00:12.940 --> 00:00:17.140
So let's give ourselves
a two by two matrix here.

00:00:17.140 --> 00:00:20.060
So, and actually, I'll
give it in general terms.

00:00:20.060 --> 00:00:24.430
So let's say that this
top-left term here is A,

00:00:24.430 --> 00:00:28.550
and then this one here is B the top-right.

00:00:28.550 --> 00:00:30.830
The bottom-left is C,

00:00:30.830 --> 00:00:34.150
and then let's call this bottom-right D.

00:00:34.150 --> 00:00:36.040
And I'm gonna do that
in a different color.

00:00:36.040 --> 00:00:38.010
So this is D right over here.

00:00:38.010 --> 00:00:39.890
the determinant of this matrix.

00:00:39.890 --> 00:00:41.930
And actually, let me
just call this matrix.

00:00:41.930 --> 00:00:44.610
Let's say that this is matrix A.

00:00:44.610 --> 00:00:47.510
So there's a bunch of ways
to call the determinant,

00:00:47.510 --> 00:00:49.420
or have the notation for the determinant.

00:00:49.420 --> 00:00:50.860
We could write it like this.

00:00:50.860 --> 00:00:51.970
We could have these little,

00:00:51.970 --> 00:00:54.060
it looks like absolute value signs,

00:00:54.060 --> 00:00:55.350
but it really means determinant

00:00:55.350 --> 00:00:57.380
when you apply it to a matrix.

00:00:57.380 --> 00:01:00.700
So the determinant of matrix A.

00:01:00.700 --> 00:01:02.310
You can write it that way.

00:01:02.310 --> 00:01:06.990
You could write it this way,
the determinant of matrix A.

00:01:08.320 --> 00:01:09.830
You could write it that way.

00:01:09.830 --> 00:01:11.060
Or you could write it this way,

00:01:11.060 --> 00:01:13.250
where you put these lines that look

00:01:13.250 --> 00:01:15.750
like big absolute value
signs instead of the brackets

00:01:15.750 --> 00:01:17.670
when you describe the numbers.

00:01:17.670 --> 00:01:19.280
So you could also write it this way.

00:01:19.280 --> 00:01:20.810
And I haven't explained
what determinant is

00:01:20.810 --> 00:01:21.890
or even how to compute it yet.

00:01:21.890 --> 00:01:23.640
I'm just talking about the notation

00:01:23.640 --> 00:01:28.140
of how you even talk about
the determinant of a matrix.

00:01:28.140 --> 00:01:29.470
So you can also write it this way,

00:01:29.470 --> 00:01:31.260
just rewrite the whole matrix

00:01:31.260 --> 00:01:34.950
with those vertical bars next to it.

00:01:34.950 --> 00:01:36.890
This is defined as,

00:01:36.890 --> 00:01:39.350
and we'll see how it's
useful in the future,

00:01:39.350 --> 00:01:42.330
the top-left time's the bottom-right.

00:01:42.330 --> 00:01:46.240
So A times D minus

00:01:49.050 --> 00:01:51.583
the top-right times the bottom-left.

00:01:52.698 --> 00:01:53.531
BC.

00:01:55.910 --> 00:01:57.370
So another way to think about it,

00:01:57.370 --> 00:02:02.370
it is just these two, the
product of these two minus,

00:02:03.210 --> 00:02:05.160
so that's those two right over there,

00:02:05.160 --> 00:02:10.160
minus the product of
these two right over here.

00:02:10.300 --> 00:02:13.230
So let's just first, before
we start to interpret this,

00:02:13.230 --> 00:02:16.440
get a little practice, just
computing a determinant.

00:02:16.440 --> 00:02:18.540
So let me give you a matrix.

00:02:18.540 --> 00:02:21.750
So let's say I have the matrix one,

00:02:21.750 --> 00:02:26.240
negative two, three, and five.

00:02:26.240 --> 00:02:29.200
Pause this video and
see if you can compute

00:02:29.200 --> 00:02:30.900
the determinant of this matrix.

00:02:30.900 --> 00:02:33.030
Let's call this matrix B.

00:02:33.030 --> 00:02:36.650
I want you to figure out
the determinant of matrix B.

00:02:36.650 --> 00:02:38.350
What is this going to be equal to?

00:02:39.680 --> 00:02:41.520
All right, now let's do this together.

00:02:41.520 --> 00:02:44.950
So you're going to have the
product of these two numbers.

00:02:44.950 --> 00:02:48.810
So we have one times five

00:02:48.810 --> 00:02:49.810
minus

00:02:50.680 --> 00:02:54.410
the product of these two numbers,

00:02:54.410 --> 00:02:58.810
which is three times negative two.

00:02:58.810 --> 00:03:01.170
And that of course, is going to be equal

00:03:01.170 --> 00:03:03.620
to one times five is five,

00:03:03.620 --> 00:03:06.510
three times negative two is negative six.

00:03:06.510 --> 00:03:10.350
But we're subtracting a negative six.

00:03:10.350 --> 00:03:15.190
Five minus negative six is the
same thing as five plus six

00:03:15.190 --> 00:03:18.680
which is going to be equal to 11.

00:03:18.680 --> 00:03:20.880
Now that we know how to
compute a determinant,

00:03:20.880 --> 00:03:21.920
in a future video,

00:03:21.920 --> 00:03:24.120
I will give you an
interesting interpretation

00:03:24.120 --> 00:03:25.423
of the determinant.


Empowering Young Women - Susan Wojcicki on Homeroom with Sal

WEBVTT
Kind: captions
Language: en

00:00:00.330 --> 00:00:02.780
- Hi, everyone. Sal Khan
here from Khan Academy.

00:00:02.780 --> 00:00:05.100
Welcome to the Homeroom,

00:00:05.100 --> 00:00:07.170
I guess we say live stream and podcast.

00:00:07.170 --> 00:00:09.740
Although we are pre-recording
today's session.

00:00:09.740 --> 00:00:12.280
First of all, Happy
International Women's Day.

00:00:12.280 --> 00:00:13.760
And we have a very exciting guest today

00:00:13.760 --> 00:00:17.080
to talk about her life and
the internet and YouTube,

00:00:17.080 --> 00:00:20.010
Susan Wojcicki, who is the CEO of YouTube,

00:00:20.010 --> 00:00:22.030
a small website that
you might have heard of

00:00:22.030 --> 00:00:23.567
that has to deal with videos.

00:00:23.567 --> 00:00:25.470
But before we jump into that conversation

00:00:25.470 --> 00:00:27.860
where we talk about all of those things

00:00:27.860 --> 00:00:29.230
I will give my standard reminders.

00:00:29.230 --> 00:00:30.910
First of all, a reminder that Khan Academy

00:00:30.910 --> 00:00:32.660
is a not-for-profit organization,

00:00:32.660 --> 00:00:34.970
and we can only exist through
philanthropic donations

00:00:34.970 --> 00:00:36.000
from folks like yourself.

00:00:36.000 --> 00:00:37.590
So if you're in a position to do so,

00:00:37.590 --> 00:00:40.740
please go to khanacademy.org/donate.

00:00:40.740 --> 00:00:42.320
I also wanna give a special shout out

00:00:42.320 --> 00:00:45.440
to several organizations that stepped up,

00:00:45.440 --> 00:00:47.160
especially during the pandemic,

00:00:47.160 --> 00:00:49.420
when they realized that
Khan Academy's traffic

00:00:49.420 --> 00:00:50.810
was three times normal,

00:00:50.810 --> 00:00:52.220
and we were running at a deficit,

00:00:52.220 --> 00:00:53.960
and we wanted to accelerate
a whole bunch of things

00:00:53.960 --> 00:00:55.260
to support more folks.

00:00:55.260 --> 00:00:58.910
So special thanks to Bank of
America, AT&T, Google.org,

00:00:58.910 --> 00:01:01.190
Novartis, Fastly and General Motors

00:01:01.190 --> 00:01:03.170
for stepping up and
helping us fill that gap.

00:01:03.170 --> 00:01:05.020
But we still need more support,

00:01:05.020 --> 00:01:07.060
especially as we go into 2021.

00:01:07.060 --> 00:01:09.170
So anything you can do
is much appreciated.

00:01:09.170 --> 00:01:10.530
And then the last announcement,

00:01:10.530 --> 00:01:13.460
there was a version of
this of this live stream

00:01:13.460 --> 00:01:15.100
that you can get in podcast form,

00:01:15.100 --> 00:01:16.660
wherever you get your podcasts.

00:01:16.660 --> 00:01:19.630
Homeroom with Sal the Podcast.

00:01:19.630 --> 00:01:23.710
So with that, I am excited
to introduce Susan Wojcicki.

00:01:23.710 --> 00:01:25.830
Susan, good to see you.

00:01:25.830 --> 00:01:27.810
- Thank you for having me, Sal.

00:01:27.810 --> 00:01:28.903
It's good to be here.

00:01:30.120 --> 00:01:31.050
- Great to have you here.

00:01:31.050 --> 00:01:33.900
And you know, we've known
each other for a while.

00:01:33.900 --> 00:01:36.700
You know, I've been known to
do a few things on YouTube.

00:01:38.420 --> 00:01:40.430
- We've known each other
for many, many years.

00:01:40.430 --> 00:01:42.800
I can't even remember when we first met.

00:01:42.800 --> 00:01:44.760
It's been so long.

00:01:44.760 --> 00:01:46.440
- Oh, it's probably on
the order of 10 years,

00:01:46.440 --> 00:01:47.790
and I know your mother.

00:01:47.790 --> 00:01:51.260
We don't live too far
away from each other.

00:01:51.260 --> 00:01:53.350
Well, there's so much I
wanna talk to you about.

00:01:53.350 --> 00:01:56.060
I think most people know about YouTube,

00:01:56.060 --> 00:01:58.640
but I think it's always
interesting to hear about

00:01:59.690 --> 00:02:03.040
the organization from
the CEO's point of view,

00:02:03.040 --> 00:02:05.520
especially what do you hope it becomes.

00:02:05.520 --> 00:02:08.720
So what's your best sense
of the mission of YouTube,

00:02:08.720 --> 00:02:10.880
or what do you think it
can become over the next,

00:02:10.880 --> 00:02:12.063
let's say, 10 years?

00:02:12.910 --> 00:02:14.820
- Yeah. Well, so we have a mission.

00:02:14.820 --> 00:02:16.300
So I'll tell you what the mission is,

00:02:16.300 --> 00:02:20.970
which is to give everyone a
voice and show them the world.

00:02:20.970 --> 00:02:24.080
And so if you look at the first part,

00:02:24.080 --> 00:02:25.410
to give everyone a voice,

00:02:25.410 --> 00:02:28.290
how do we enable anyone who
wants to share something

00:02:28.290 --> 00:02:29.123
with the world,

00:02:29.123 --> 00:02:30.810
how to enable them to do that?

00:02:30.810 --> 00:02:35.360
So, I think YouTube has
really made a lot of...

00:02:35.360 --> 00:02:37.270
We've been revolutionary
in many ways, right?

00:02:37.270 --> 00:02:40.500
We have millions of channels and creators,

00:02:40.500 --> 00:02:41.930
but we still have a lot of work to do

00:02:41.930 --> 00:02:44.650
to continue to enable
people all over the world

00:02:44.650 --> 00:02:46.900
to create video and make it easier,

00:02:46.900 --> 00:02:49.200
and continue to grow that,

00:02:49.200 --> 00:02:50.240
but show them the world.

00:02:50.240 --> 00:02:52.410
I think that's actually
where we're really aligned

00:02:52.410 --> 00:02:53.560
in terms of our mission,

00:02:53.560 --> 00:02:56.600
so that people everywhere
can come to YouTube

00:02:56.600 --> 00:02:57.910
and learn anything they want,

00:02:57.910 --> 00:03:00.940
or experience any kind
of music, entertainment,

00:03:00.940 --> 00:03:02.650
look up any kind of information.

00:03:02.650 --> 00:03:05.810
And so I've also said that
YouTube, in some ways,

00:03:05.810 --> 00:03:09.623
is like a public video library,

00:03:10.610 --> 00:03:13.340
and we keep growing and growing

00:03:13.340 --> 00:03:15.080
in terms of offering new topics

00:03:15.080 --> 00:03:17.200
and we have books from like books,

00:03:17.200 --> 00:03:19.970
like videos from new people.

00:03:19.970 --> 00:03:23.320
And our goal is just to
continue to be a resource

00:03:23.320 --> 00:03:25.980
for people around the world to learn.

00:03:25.980 --> 00:03:27.610
And I've been really inspired by that.

00:03:27.610 --> 00:03:29.470
I sometimes see in different
parts of the world,

00:03:29.470 --> 00:03:30.303
wherever I go,

00:03:30.303 --> 00:03:32.050
people tell me what
they learned on YouTube.

00:03:32.050 --> 00:03:34.973
So that's something we
wanna continue to grow.

00:03:36.270 --> 00:03:37.730
- I think that's the surprising thing.

00:03:37.730 --> 00:03:38.970
You know, when YouTube was just starting

00:03:38.970 --> 00:03:39.803
to get off the ground

00:03:39.803 --> 00:03:41.710
and people started to associate it with,

00:03:41.710 --> 00:03:43.120
you know, just entertainment,

00:03:43.120 --> 00:03:44.830
but very quickly humanity

00:03:44.830 --> 00:03:47.230
realized that kind of
knowledge could be shared.

00:03:47.230 --> 00:03:52.230
And I actually think YouTube
will go down in world history

00:03:52.340 --> 00:03:54.240
as a moment in human history,

00:03:54.240 --> 00:03:55.820
where for, you know,

00:03:55.820 --> 00:03:57.610
humans are separate themselves

00:03:57.610 --> 00:03:59.820
from the rest of the animal
kingdom by having culture

00:03:59.820 --> 00:04:01.340
and having shared knowledge,

00:04:01.340 --> 00:04:03.080
which for many tens of thousands of years

00:04:03.080 --> 00:04:04.950
happened through an oral tradition,

00:04:04.950 --> 00:04:07.690
then we invented a writing,

00:04:07.690 --> 00:04:09.350
and then that allowed it to persist,

00:04:09.350 --> 00:04:12.720
and not kind of lose information
as that information spread,

00:04:12.720 --> 00:04:14.950
but writing loses a
little bit of the oral.

00:04:14.950 --> 00:04:17.830
And now with on-demand video and YouTube

00:04:18.790 --> 00:04:20.640
and mass distribution of it,

00:04:20.640 --> 00:04:22.220
you kind of have all of the above,

00:04:22.220 --> 00:04:24.490
that any one person can express their oral

00:04:24.490 --> 00:04:26.970
or their video or the visual
tradition and their knowledge,

00:04:26.970 --> 00:04:28.280
and then it's literally available

00:04:28.280 --> 00:04:30.270
to every human being on the planet.

00:04:30.270 --> 00:04:31.750
Do you all ever view yourself that way,

00:04:31.750 --> 00:04:33.360
as like the globe's,

00:04:33.360 --> 00:04:35.080
I guess you did say it's the library,

00:04:35.080 --> 00:04:36.540
it's the brain,

00:04:36.540 --> 00:04:39.793
the knowledge of humanity
is literally on YouTube.

00:04:40.970 --> 00:04:42.280
- I definitely see the impact,

00:04:42.280 --> 00:04:44.360
because people everywhere
tell me what they learn,

00:04:44.360 --> 00:04:47.200
and especially now, during the pandemic,

00:04:47.200 --> 00:04:48.233
we played a really key role.

00:04:48.233 --> 00:04:50.510
A lot of people had to do
things for the first time,

00:04:50.510 --> 00:04:53.340
like fix something in their
house, give a haircut,

00:04:53.340 --> 00:04:54.460
learn a new skill.

00:04:54.460 --> 00:04:56.240
And the fact that YouTube could do that

00:04:56.240 --> 00:04:58.500
and could be there in
that moment of crisis

00:04:58.500 --> 00:05:00.580
was really, really valuable.

00:05:00.580 --> 00:05:01.727
So I definitely understand that,

00:05:01.727 --> 00:05:03.790
and our goal is to continue to grow that

00:05:03.790 --> 00:05:05.130
and support those use cases,

00:05:05.130 --> 00:05:07.093
so everybody can have that resource.

00:05:08.260 --> 00:05:09.240
- Absolutely, and obviously,

00:05:09.240 --> 00:05:10.800
most people who are watching this,

00:05:10.800 --> 00:05:13.290
many of them who are
watching it on YouTube,

00:05:13.290 --> 00:05:16.240
know that, you know, I showed
up on people's radar...

00:05:16.240 --> 00:05:17.710
You know, Khan Academy
has a lot of things.

00:05:17.710 --> 00:05:19.120
We have videos and exercises,

00:05:19.120 --> 00:05:21.460
but it's the YouTube
that really helped people

00:05:21.460 --> 00:05:22.780
know what we're all about,

00:05:22.780 --> 00:05:24.190
and was an easy way to discover.

00:05:24.190 --> 00:05:25.050
You mentioned haircuts.

00:05:25.050 --> 00:05:26.780
My wife watched a couple
of YouTube videos,

00:05:26.780 --> 00:05:28.520
and, you know, I think it's...

00:05:28.520 --> 00:05:29.610
You know, my hair has issues,

00:05:29.610 --> 00:05:31.930
but it's one of the better
haircuts that I've gotten.

00:05:31.930 --> 00:05:32.840
And I've fixed a toilet.

00:05:32.840 --> 00:05:34.230
I fixed the toilet twice

00:05:34.230 --> 00:05:36.100
over the last nine months

00:05:36.100 --> 00:05:37.490
based on YouTube videos.

00:05:37.490 --> 00:05:39.100
And I think they're working.

00:05:39.100 --> 00:05:41.490
So that's absolutely true.

00:05:41.490 --> 00:05:44.070
You know, on the other
side of that though,

00:05:44.070 --> 00:05:45.400
there's a lot of conversation

00:05:45.400 --> 00:05:48.300
about misinformation and
the spreading of, you know,

00:05:48.300 --> 00:05:50.520
how people get into their own silos.

00:05:50.520 --> 00:05:52.180
How do y'all think about that on YouTube?

00:05:52.180 --> 00:05:54.350
How do y'all try to make sense of people

00:05:54.350 --> 00:05:56.910
who are spreading misinformation,

00:05:56.910 --> 00:05:59.330
or, you know, people just
gravitating to things

00:05:59.330 --> 00:06:01.980
that already confirm whatever
biases they might have?

00:06:03.340 --> 00:06:06.120
- So great question and
really important question.

00:06:06.120 --> 00:06:08.630
And we've put a huge amount of effort

00:06:08.630 --> 00:06:10.780
to figure out the right
solutions for that.

00:06:10.780 --> 00:06:13.360
And so basically we
talk about all this work

00:06:13.360 --> 00:06:15.100
around responsibility.

00:06:15.100 --> 00:06:18.790
And so we have what we call
the four Rs of responsibility.

00:06:18.790 --> 00:06:22.080
And the first one is about content

00:06:22.080 --> 00:06:23.360
that we would remove

00:06:23.360 --> 00:06:25.950
if it is content that we think could lead

00:06:25.950 --> 00:06:27.120
to real-world harm.

00:06:27.120 --> 00:06:29.700
So like, let's just talk about COVID,

00:06:29.700 --> 00:06:31.760
just to put this in perspective.

00:06:31.760 --> 00:06:35.180
So there were different
conspiracies that came out,

00:06:35.180 --> 00:06:39.790
like one of them was that
COVID came from 5G cell towers,

00:06:39.790 --> 00:06:44.373
and it goes against all consensus,

00:06:45.620 --> 00:06:46.453
from medical consensus.

00:06:46.453 --> 00:06:48.267
And so that was something
where we would say,

00:06:48.267 --> 00:06:49.590
"That's clearly not true."

00:06:49.590 --> 00:06:50.423
We need to remove it,

00:06:50.423 --> 00:06:53.230
because people were
destroying cell towers,

00:06:53.230 --> 00:06:55.380
and we also don't want people to go out

00:06:55.380 --> 00:06:56.560
and then do risky behavior.

00:06:56.560 --> 00:06:58.530
So we are able to work
with medical professionals

00:06:58.530 --> 00:06:59.480
to find content

00:07:02.768 --> 00:07:04.240
that was clearly violative.

00:07:04.240 --> 00:07:07.610
And again, we work with the
medical professionals on that.

00:07:07.610 --> 00:07:09.650
But then we also raised up information,

00:07:09.650 --> 00:07:14.303
so information that we
knew that was accurate.

00:07:16.040 --> 00:07:17.300
So like how to wash your hands.

00:07:17.300 --> 00:07:18.450
I never thought we'd serve so many

00:07:18.450 --> 00:07:20.770
how to wash your hand videos.

00:07:20.770 --> 00:07:22.930
We worked with 85 different

00:07:22.930 --> 00:07:24.580
health professional organizations

00:07:24.580 --> 00:07:26.760
from around the world,

00:07:26.760 --> 00:07:30.560
and we made sure that all of
that information was delivered.

00:07:30.560 --> 00:07:31.620
So whether you did a search,

00:07:31.620 --> 00:07:32.570
whether you watched the video,

00:07:32.570 --> 00:07:35.560
you could link and you could
see authoritative information.

00:07:35.560 --> 00:07:38.230
And then there's some content
that's just borderline,

00:07:38.230 --> 00:07:42.550
like it might be something that
isn't really a big problem,

00:07:42.550 --> 00:07:43.540
but it's low quality.

00:07:43.540 --> 00:07:44.460
And that's just something

00:07:44.460 --> 00:07:46.890
that we are less likely
to recommend to our users,

00:07:46.890 --> 00:07:49.390
because we wanna give them
high quality information.

00:07:49.390 --> 00:07:51.210
We don't want them to
come and see something

00:07:51.210 --> 00:07:54.020
that says like, "Aliens
landed in your backyard."

00:07:54.020 --> 00:07:55.820
That's very unlikely.

00:07:55.820 --> 00:07:58.860
And so, again, we don't
want to go too far,

00:07:58.860 --> 00:08:00.870
and say, hey, we're
restricting free speech,

00:08:00.870 --> 00:08:03.190
because that's very important too,

00:08:03.190 --> 00:08:07.380
that we can enable a broad set
of opinions and perspectives.

00:08:07.380 --> 00:08:12.380
So we also are reducing
information that is low quality

00:08:13.560 --> 00:08:16.820
in terms of how we handle
that in our recommendations.

00:08:16.820 --> 00:08:18.640
- No, that last point, I
always like to clarify,

00:08:18.640 --> 00:08:20.570
whenever people say that, you know,

00:08:20.570 --> 00:08:21.700
this is reducing free speech,

00:08:21.700 --> 00:08:22.900
I was like, "You know, free speech

00:08:22.900 --> 00:08:24.650
is the right to say things that,

00:08:24.650 --> 00:08:27.110
first of all, you know, somehow
do not undermine government

00:08:27.110 --> 00:08:28.790
or would hurt people,

00:08:28.790 --> 00:08:29.960
but you have the right to say it,

00:08:29.960 --> 00:08:31.340
but you don't have the right to for it

00:08:31.340 --> 00:08:34.840
to be amplified by other media companies."

00:08:34.840 --> 00:08:36.390
If you go back 100 years ago,

00:08:36.390 --> 00:08:37.810
I could say whatever I want,

00:08:37.810 --> 00:08:40.190
I could complain about government,

00:08:40.190 --> 00:08:41.930
or come up with conspiracy theories,

00:08:41.930 --> 00:08:43.380
but it doesn't mean
that the New York Times

00:08:43.380 --> 00:08:45.300
have to publish whatever I had to say.

00:08:45.300 --> 00:08:46.810
And there's an analogy now

00:08:46.810 --> 00:08:48.670
that it does not have to be validated,

00:08:48.670 --> 00:08:51.880
or you don't have the
right to be amplified.

00:08:51.880 --> 00:08:54.050
So I think it's an interesting nuance.

00:08:54.050 --> 00:08:56.170
Yes, you can't be arrested for coming up

00:08:56.170 --> 00:08:57.140
with a conspiracy theory,

00:08:57.140 --> 00:08:59.690
but you can't just spread it willy nilly,

00:08:59.690 --> 00:09:01.720
and say, "That's my right.

00:09:01.720 --> 00:09:03.930
You know, I would love to dig a little bit

00:09:03.930 --> 00:09:08.090
into your journey to
becoming CEO of YouTube.

00:09:08.090 --> 00:09:10.430
We have a lot of young
people who watch this.

00:09:10.430 --> 00:09:12.060
It's International Women's Day.

00:09:12.060 --> 00:09:13.330
I think there's a lot of young women

00:09:13.330 --> 00:09:16.490
who look up to you as a
real leader in industry

00:09:16.490 --> 00:09:17.690
across the board.

00:09:17.690 --> 00:09:19.930
When you were young, what were you like,

00:09:19.930 --> 00:09:22.430
and is this what you thought
you were going to do?

00:09:23.530 --> 00:09:25.240
- No, I had no idea

00:09:25.240 --> 00:09:26.870
this is what I was gonna do.

00:09:26.870 --> 00:09:29.840
And maybe I'm showing
my age by saying this,

00:09:29.840 --> 00:09:32.050
but we didn't have the
internet when I was young,

00:09:32.050 --> 00:09:34.930
so I couldn't have even imagined that.

00:09:34.930 --> 00:09:39.620
And I mean, I think as a young kid,

00:09:39.620 --> 00:09:40.743
what was I like?

00:09:41.670 --> 00:09:44.770
First of all, I was really
into doing arts and crafts.

00:09:44.770 --> 00:09:46.840
I was really into being creative

00:09:46.840 --> 00:09:47.673
and making things,

00:09:47.673 --> 00:09:51.140
like I would make paper and pot holders.

00:09:51.140 --> 00:09:53.600
My first business was making spice ropes

00:09:53.600 --> 00:09:54.840
and selling them to my neighbor.

00:09:54.840 --> 00:09:57.490
So I just like to make stuff.
- What's a spice rope?

00:09:58.740 --> 00:10:03.510
- I would braid yarn and then
tie cinnamon sticks to it

00:10:03.510 --> 00:10:07.230
and take colored fabric
and put spices in there.

00:10:07.230 --> 00:10:10.040
And I just would make stuff.

00:10:10.040 --> 00:10:15.040
And for me, I had this realization

00:10:16.698 --> 00:10:19.830
that technology was about creation.

00:10:19.830 --> 00:10:23.053
It was about making things
and creating things.

00:10:25.120 --> 00:10:26.710
A lot of people didn't seem to see that,

00:10:26.710 --> 00:10:28.370
especially not then,

00:10:28.370 --> 00:10:29.450
but I totally got it.

00:10:29.450 --> 00:10:32.230
I was like, "Wow, I can make all kinds

00:10:32.230 --> 00:10:33.810
of really interesting software,

00:10:33.810 --> 00:10:37.890
and it can be distributed,

00:10:37.890 --> 00:10:40.280
and so, so many people can see it

00:10:40.280 --> 00:10:43.126
and they can use it and
I can interact with them.

00:10:43.126 --> 00:10:46.063
And once I got that idea,

00:10:47.130 --> 00:10:49.940
I just said like, "Oh,
I have to be in tech.

00:10:49.940 --> 00:10:52.850
This is the best field for me

00:10:52.850 --> 00:10:53.970
based on all my interests

00:10:53.970 --> 00:10:56.270
with the creativity and making things,

00:10:56.270 --> 00:10:58.700
and seeing how I could
have an impact that way."

00:10:58.700 --> 00:11:00.640
I didn't know where it was gonna lead,

00:11:00.640 --> 00:11:03.290
but as long as I was
making things, I was happy,

00:11:03.290 --> 00:11:06.273
and that's what got me started in tech.

00:11:07.190 --> 00:11:08.170
- No, very similar to me.

00:11:08.170 --> 00:11:09.700
It's all about this notion of creation,

00:11:09.700 --> 00:11:12.990
and that you can create things
that have incredible scale,

00:11:12.990 --> 00:11:15.140
incredible impact.

00:11:15.140 --> 00:11:16.990
And once you went into tech,

00:11:16.990 --> 00:11:18.430
what did you think you
were gonna actually...

00:11:18.430 --> 00:11:19.550
How did you get started?

00:11:19.550 --> 00:11:23.273
Did you take a traditional
software engineering route?

00:11:24.490 --> 00:11:27.877
Connect the dots between
this interest in creation

00:11:27.877 --> 00:11:29.163
and where you are now.

00:11:30.230 --> 00:11:32.090
- Well, I took a computer science class

00:11:32.090 --> 00:11:33.320
my senior year in college.

00:11:33.320 --> 00:11:36.120
I took the computer science
for computer science majors,

00:11:37.970 --> 00:11:40.650
At the time I thought, "Oh, it's too late.

00:11:40.650 --> 00:11:42.207
Oh, I'm too old."

00:11:43.447 --> 00:11:45.030
Like, I was a humanities major,

00:11:45.030 --> 00:11:47.760
so I was like, "I must be
too old to change careers,"

00:11:47.760 --> 00:11:48.593
'cause I was--

00:11:48.593 --> 00:11:49.900
- I find it funny when a 20-year-old

00:11:49.900 --> 00:11:51.587
says they're too old, 21.

00:11:51.587 --> 00:11:52.480
- I thought I was too old,

00:11:52.480 --> 00:11:56.060
as 20 or 21-year-old, to start
learning computer science,

00:11:56.060 --> 00:11:57.790
'cause I had friends and they were majors,

00:11:57.790 --> 00:11:59.070
and they had taken it for three years,

00:11:59.070 --> 00:12:01.300
and we were all about to graduate.

00:12:01.300 --> 00:12:05.900
But I realized that I
wanted to do something

00:12:05.900 --> 00:12:06.733
in computer science.

00:12:06.733 --> 00:12:10.800
And so that was my first role,

00:12:10.800 --> 00:12:11.840
or that was my first, you know,

00:12:11.840 --> 00:12:13.700
that's when I was academically engaged

00:12:13.700 --> 00:12:14.690
with computer science,

00:12:14.690 --> 00:12:17.880
and then I grew up in the Palo Alto area.

00:12:17.880 --> 00:12:20.130
So I think that probably
had something to do with it.

00:12:20.130 --> 00:12:23.100
And I came back after college,

00:12:23.100 --> 00:12:28.100
and I wound up working at this
educational software startup.

00:12:28.290 --> 00:12:31.010
So here I am, Sal,

00:12:31.010 --> 00:12:33.403
I don't know, many, many years later,

00:12:34.666 --> 00:12:37.570
working with you around education.

00:12:37.570 --> 00:12:40.300
So I had that interest then.

00:12:40.300 --> 00:12:42.260
I still have that interest now,

00:12:42.260 --> 00:12:44.130
but I was just a project manager

00:12:44.130 --> 00:12:48.550
for making software for
kids around education,

00:12:48.550 --> 00:12:50.400
and I loved it.

00:12:50.400 --> 00:12:52.539
It was creation.

00:12:52.539 --> 00:12:54.530
Kids would write about
how they use the software,

00:12:54.530 --> 00:12:57.630
how they learn something
and the impact it had.

00:12:57.630 --> 00:13:00.000
And so I just said like,
"This is what I'm gonna do.

00:13:00.000 --> 00:13:01.807
I'm so committed to this."

00:13:04.222 --> 00:13:06.590
I can keep going. You wanna know more?

00:13:06.590 --> 00:13:09.460
- No, I do. I actually never
knew about this chapter.

00:13:09.460 --> 00:13:10.570
I mean, I'm especially curious

00:13:10.570 --> 00:13:13.110
about what do you think it
was that you told yourself

00:13:13.110 --> 00:13:14.500
or the skills that you brought

00:13:14.500 --> 00:13:17.280
to the table that allowed
you to really thrive

00:13:17.280 --> 00:13:18.330
in this world,

00:13:18.330 --> 00:13:22.010
and obviously, you know, keep
rising through the ranks?

00:13:22.010 --> 00:13:24.740
You know, you joined Google
at a very early stage,

00:13:24.740 --> 00:13:26.793
and then now as CEO of YouTube,

00:13:27.710 --> 00:13:28.940
you know, I know it's a
hard question to answer,

00:13:28.940 --> 00:13:30.140
'cause you're a humble person,

00:13:30.140 --> 00:13:33.370
but be not so humble for a few seconds.

00:13:33.370 --> 00:13:34.330
- Sure.

00:13:34.330 --> 00:13:36.120
If I look back at my career,

00:13:36.120 --> 00:13:39.710
there were a few key things
that really helped me.

00:13:39.710 --> 00:13:43.053
One of them was, first of all,

00:13:45.624 --> 00:13:47.100
I was just looking to do
something interesting.

00:13:47.100 --> 00:13:47.933
I was just thinking,

00:13:47.933 --> 00:13:51.567
"How can I use my skills
to help create something

00:13:51.567 --> 00:13:53.277
that will be used by people,

00:13:53.277 --> 00:13:54.330
and that will be useful

00:13:54.330 --> 00:13:55.790
and make the world a better place?

00:13:55.790 --> 00:13:57.540
And when I joined Google,

00:13:57.540 --> 00:14:00.260
I was in place 16 of Google.

00:14:00.260 --> 00:14:01.640
When I joined Google,

00:14:01.640 --> 00:14:03.350
nobody thought that Google

00:14:03.350 --> 00:14:05.260
was that interesting of a company,

00:14:05.260 --> 00:14:07.970
but I saw that it was enabling people

00:14:07.970 --> 00:14:09.870
to find information in new ways.

00:14:09.870 --> 00:14:13.610
And so being able to just
focus on what was important,

00:14:13.610 --> 00:14:15.330
what I saw was adding value,

00:14:15.330 --> 00:14:17.340
whether or not other people agreed or not,

00:14:17.340 --> 00:14:19.970
was part of what helped me.

00:14:19.970 --> 00:14:21.500
I think it was the same thing for YouTube.

00:14:21.500 --> 00:14:23.470
When I first started working on YouTube,

00:14:23.470 --> 00:14:26.230
nobody thought it was that big a deal.

00:14:26.230 --> 00:14:29.710
They thought it was a small little company

00:14:29.710 --> 00:14:31.660
with like a lot of cats on skateboards.

00:14:31.660 --> 00:14:33.070
It wasn't really going anywhere,

00:14:33.070 --> 00:14:35.120
but I saw that people could use it

00:14:35.120 --> 00:14:37.760
for creating and sharing ideas,

00:14:37.760 --> 00:14:38.760
and information,

00:14:38.760 --> 00:14:43.250
and new musicians and
artists and creators.

00:14:43.250 --> 00:14:46.930
So seeing ideas early
and believing in them

00:14:46.930 --> 00:14:48.670
has definitely helped me.

00:14:48.670 --> 00:14:52.270
But then I would say there's a part two,

00:14:52.270 --> 00:14:56.060
which was maybe less inspiration
and more perspiration,

00:14:56.060 --> 00:14:58.350
which is just sticking with it,

00:14:58.350 --> 00:15:01.270
and working hard and not giving up,

00:15:01.270 --> 00:15:03.200
and getting through all the hard times,

00:15:03.200 --> 00:15:06.420
and just sticking with it,

00:15:06.420 --> 00:15:10.120
keep working on it, keep
waking up every day,

00:15:10.120 --> 00:15:13.320
thinking about how you can
make the company better,

00:15:13.320 --> 00:15:15.160
and add value,

00:15:15.160 --> 00:15:17.790
and get through the tough times.

00:15:17.790 --> 00:15:21.660
So I'd say that those
are the two key parts,

00:15:21.660 --> 00:15:23.510
the inspiration and the perspiration.

00:15:24.370 --> 00:15:25.410
- It makes a lot of sense.

00:15:25.410 --> 00:15:26.740
And I have so many questions for you,

00:15:26.740 --> 00:15:28.010
but I know we have a lot of questions

00:15:28.010 --> 00:15:30.890
that have come in
appropriately for you on video.

00:15:30.890 --> 00:15:33.110
So the first question
we have is from Izzy,

00:15:33.110 --> 00:15:34.813
if we could watch that video.

00:15:34.813 --> 00:15:36.687
- I was wondering what you wanted to do

00:15:36.687 --> 00:15:37.520
when you were my age.

00:15:37.520 --> 00:15:40.193
And did you ever think you'd
be the CEO of a huge company?

00:15:43.400 --> 00:15:45.270
- No, I never thought I'd would be the CEO

00:15:45.270 --> 00:15:46.290
of a huge company.

00:15:46.290 --> 00:15:49.680
And when I was your age,

00:15:49.680 --> 00:15:51.950
I probably wanted to...

00:15:51.950 --> 00:15:53.800
I was just interested in
a lot of different things.

00:15:53.800 --> 00:15:56.950
I didn't really know what
the future held for me,

00:15:56.950 --> 00:15:58.980
but I was interested in arts and crafts.

00:15:58.980 --> 00:16:00.510
I was interested in science.

00:16:00.510 --> 00:16:03.840
I was interested in entrepreneurship.

00:16:03.840 --> 00:16:05.470
I would just start things.

00:16:05.470 --> 00:16:07.430
And like I said, I would make things

00:16:07.430 --> 00:16:09.300
and sell it to my neighbors.

00:16:09.300 --> 00:16:14.050
And all of those turned out in
the end to be useful skills.

00:16:14.050 --> 00:16:17.190
So I just encourage all of
you to explore the world,

00:16:17.190 --> 00:16:18.860
find what you love,

00:16:18.860 --> 00:16:23.570
find the areas that you
wanna keep working on,

00:16:23.570 --> 00:16:26.390
and that ultimately will
lead you to somewhere,

00:16:26.390 --> 00:16:28.300
because to choose a career,

00:16:28.300 --> 00:16:29.610
to choose a profession,

00:16:29.610 --> 00:16:32.550
it has to be something
that is meaningful for you.

00:16:32.550 --> 00:16:34.770
It'll be much easier and
you'll do a better job

00:16:34.770 --> 00:16:35.900
if it's meaningful to you.

00:16:35.900 --> 00:16:39.060
So choose something that
you enjoy doing every day,

00:16:39.060 --> 00:16:42.620
and that you see benefits the world,

00:16:42.620 --> 00:16:45.603
and that, ultimately,
you derive meaning from.

00:16:47.660 --> 00:16:48.493
- Completely agree.

00:16:48.493 --> 00:16:50.853
And the next question
we have is from Lily.

00:16:51.690 --> 00:16:53.090
- For young women who are looking

00:16:53.090 --> 00:16:56.820
into being in management
positions or positions of power,

00:16:56.820 --> 00:16:58.090
what advice do you have for them

00:16:58.090 --> 00:17:00.510
in trying to get past
those gender stereotypes

00:17:00.510 --> 00:17:01.410
of being too pushy

00:17:01.410 --> 00:17:03.660
or too bossy when try
to achieve their goals?

00:17:05.780 --> 00:17:09.740
- So there are definitely
a lot of challenges.

00:17:09.740 --> 00:17:13.750
And some of the ways
that I have overcome them

00:17:13.750 --> 00:17:16.860
is by, first of all, working really hard,

00:17:16.860 --> 00:17:19.060
which I'm sure all of you do.

00:17:19.060 --> 00:17:24.060
And also I'd say, with
some of the stereotypes,

00:17:24.090 --> 00:17:27.340
or people maybe who are
maybe not as supportive,

00:17:27.340 --> 00:17:30.040
I've tried to ignore the people

00:17:30.040 --> 00:17:31.410
who might be less supportive

00:17:31.410 --> 00:17:33.660
and make friends with the people who are.

00:17:33.660 --> 00:17:35.360
And so I've found it really valuable

00:17:35.360 --> 00:17:36.770
over the course of my career

00:17:36.770 --> 00:17:38.850
to figure out who my allies are,

00:17:38.850 --> 00:17:40.160
to work closely with them,

00:17:40.160 --> 00:17:42.343
develop close relationships with them,

00:17:43.890 --> 00:17:47.380
and just continue doing
the work that you're doing.

00:17:47.380 --> 00:17:50.090
And I do think we're at a time

00:17:50.090 --> 00:17:53.180
where companies are working really hard

00:17:53.180 --> 00:17:55.530
to have diverse workforces,

00:17:55.530 --> 00:17:57.340
because we recognize that diversity

00:17:57.340 --> 00:17:58.710
makes a stronger company,

00:17:58.710 --> 00:18:00.440
it makes a better product,

00:18:00.440 --> 00:18:03.920
and I encourage all of you
to pursue your passions,

00:18:03.920 --> 00:18:05.960
and just to continue to work hard,

00:18:05.960 --> 00:18:09.200
and don't give up and find your allies.

00:18:09.200 --> 00:18:12.773
And if you find someone
who's not supportive,

00:18:15.616 --> 00:18:17.290
just do your best to, you know,

00:18:17.290 --> 00:18:19.110
keep working through that.

00:18:19.110 --> 00:18:23.290
And certainly, while there
are different stereotypes,

00:18:23.290 --> 00:18:24.830
the stereotypes are always changing,

00:18:24.830 --> 00:18:28.280
and I really hope by the time
that a lot of you grow up,

00:18:28.280 --> 00:18:30.170
that some of the stereotypes you mentioned

00:18:30.170 --> 00:18:32.973
are not anything that you
have to face in the future.

00:18:34.200 --> 00:18:35.400
- And just following up on that,

00:18:35.400 --> 00:18:38.280
you know, for those who don't know, Susan,

00:18:38.280 --> 00:18:40.910
you and your siblings and your
mother are kind of famous.

00:18:40.910 --> 00:18:42.750
You know, as sisters,

00:18:42.750 --> 00:18:45.670
all of you have been wildly successful.

00:18:45.670 --> 00:18:47.060
You know, you have a
sister who's a physician,

00:18:47.060 --> 00:18:50.500
you have a sister who is a CEO of 23andMe.

00:18:50.500 --> 00:18:54.878
Your mother is world
famous as an educator,

00:18:54.878 --> 00:18:57.930
a journalism teacher,
et cetera, et cetera.

00:18:57.930 --> 00:19:00.410
Is there something that
your mother gave you

00:19:00.410 --> 00:19:02.660
or you had between your
yourselves as sisters

00:19:02.660 --> 00:19:03.830
that you could share,

00:19:03.830 --> 00:19:06.320
with kind of sisters around the world,

00:19:06.320 --> 00:19:07.470
that really helped you?

00:19:08.460 --> 00:19:11.900
- I wish I could say
it was just one thing,

00:19:11.900 --> 00:19:16.900
but I do think the one thing
my mom gave to all of us

00:19:17.250 --> 00:19:22.233
was certainly the focus on persistence,

00:19:23.550 --> 00:19:27.220
believing in yourself and
not getting embarrassed.

00:19:27.220 --> 00:19:31.120
So my mom was always the first person

00:19:31.120 --> 00:19:34.840
to ask a hard question in an audience.

00:19:34.840 --> 00:19:39.840
Like, she used to always
be the one who would say...

00:19:40.420 --> 00:19:42.110
She felt like if she had been wrong,

00:19:42.110 --> 00:19:43.920
she needed to speak up about it.

00:19:43.920 --> 00:19:46.340
And sometimes as a kid, that
was really embarrassing,

00:19:46.340 --> 00:19:47.630
but I learned over time,

00:19:47.630 --> 00:19:49.140
it's really important to use your voice.

00:19:49.140 --> 00:19:51.580
It's really important
to say what you believe

00:19:51.580 --> 00:19:54.160
and to speak up for yourself.

00:19:54.160 --> 00:19:57.800
And I do think that those
skills have helped all of us,

00:19:57.800 --> 00:19:59.070
because if you believe in yourself,

00:19:59.070 --> 00:20:00.200
you speak up for yourself,

00:20:00.200 --> 00:20:01.290
but you're working hard

00:20:01.290 --> 00:20:03.520
and doing a great job
of what you're doing,

00:20:03.520 --> 00:20:05.600
you're gonna find a way to be successful.

00:20:05.600 --> 00:20:08.350
And I think that we
learned a lot of skills

00:20:08.350 --> 00:20:10.450
from my mom and my dad,

00:20:10.450 --> 00:20:11.400
who's the professor,

00:20:11.400 --> 00:20:15.053
and who was consistently hardworking,

00:20:18.191 --> 00:20:21.820
and we learned that those
are all things that it takes.

00:20:21.820 --> 00:20:24.750
And if you keep it up and work hard,

00:20:24.750 --> 00:20:29.750
you'll end up with something
that is compelling for you.

00:20:31.310 --> 00:20:35.293
- Yeah, well, we have another
question here from Imari.

00:20:35.293 --> 00:20:37.660
- What are some activities or actions

00:20:37.660 --> 00:20:40.300
that you recommend for
young women entering college

00:20:40.300 --> 00:20:42.280
to prepare them for career success?

00:20:45.280 --> 00:20:47.080
- So for career success,

00:20:47.080 --> 00:20:48.590
for people who are entering college

00:20:48.590 --> 00:20:50.120
or entering the workforce,

00:20:50.120 --> 00:20:52.770
I would really encourage
you to think about

00:20:52.770 --> 00:20:53.980
what is meaningful for you,

00:20:53.980 --> 00:20:58.240
because it's very hard to do
a job that you don't like.

00:20:58.240 --> 00:21:02.300
You have to find something
that really speaks to you.

00:21:02.300 --> 00:21:04.550
And I see that among my own kids,

00:21:04.550 --> 00:21:06.550
and all the kids that I work with,

00:21:06.550 --> 00:21:08.630
that people come from
very different places.

00:21:08.630 --> 00:21:11.610
And there are very different
passions that people have.

00:21:11.610 --> 00:21:15.360
And so to the extent that
you can look inside yourself,

00:21:15.360 --> 00:21:17.810
and think about what would
be really meaningful for you,

00:21:17.810 --> 00:21:20.640
and find a way to explore that,

00:21:20.640 --> 00:21:24.700
and that if your work
speaks to you in a deep way,

00:21:24.700 --> 00:21:26.940
and you take meaning from it,

00:21:26.940 --> 00:21:29.410
it will help you get
through the hard times.

00:21:29.410 --> 00:21:33.480
It will help you stick with
it and make a difference.

00:21:33.480 --> 00:21:36.060
So I encourage you just
to really think about

00:21:36.060 --> 00:21:37.010
what your passions are,

00:21:37.010 --> 00:21:39.570
and you have to be practical
too, realistically,

00:21:39.570 --> 00:21:42.370
I think that's something I
learned from my mom also,

00:21:42.370 --> 00:21:44.140
like, I would have probably said, oh.

00:21:44.140 --> 00:21:45.140
If you had asked me as a kid,

00:21:45.140 --> 00:21:47.540
I've always said, "Oh, I just
want to be like an artist,

00:21:47.540 --> 00:21:49.300
and draw pictures,

00:21:49.300 --> 00:21:50.850
and, you know, make candles,"

00:21:50.850 --> 00:21:53.560
and as compelling as all of that is,

00:21:53.560 --> 00:21:54.617
she also encouraged me like,

00:21:54.617 --> 00:21:56.030
"Yes, you need to be
able to make a living.

00:21:56.030 --> 00:21:57.170
You have to be able to do something

00:21:57.170 --> 00:21:58.190
where you can support yourself."

00:21:58.190 --> 00:22:02.590
So marrying the two of
what your passion is,

00:22:02.590 --> 00:22:04.530
but where there's market and demand

00:22:04.530 --> 00:22:06.580
for the things that you're interested in,

00:22:07.630 --> 00:22:11.100
those are good places for you
to look at future careers.

00:22:11.100 --> 00:22:12.490
And also encourage
people to look at things

00:22:12.490 --> 00:22:13.323
that are growing.

00:22:13.323 --> 00:22:15.630
Like, in many ways, I
benefited from being in tech,

00:22:15.630 --> 00:22:16.930
which was a growing industry,

00:22:16.930 --> 00:22:18.590
so there were always new jobs.

00:22:18.590 --> 00:22:20.740
There was always something new to explore.

00:22:20.740 --> 00:22:22.900
And so to the extent that
you can choose an area

00:22:22.900 --> 00:22:23.860
that is expanding,

00:22:23.860 --> 00:22:25.588
that's the whole area is growing,

00:22:25.588 --> 00:22:26.640
it's gonna be easier to get more jobs.

00:22:26.640 --> 00:22:28.410
It's going to be easier to get promoted.

00:22:28.410 --> 00:22:30.680
So that's another thing to consider

00:22:30.680 --> 00:22:33.270
as you factor your future career in

00:22:33.270 --> 00:22:35.393
and what areas you're gonna go into.

00:22:37.000 --> 00:22:37.880
- No, I love that advice.

00:22:37.880 --> 00:22:39.430
I always tell folks,

00:22:39.430 --> 00:22:40.690
actually, on one part of your brain,

00:22:40.690 --> 00:22:42.000
you should be hyper pragmatic.

00:22:42.000 --> 00:22:43.420
look at the industries that are growing,

00:22:43.420 --> 00:22:44.810
that compensate well,

00:22:44.810 --> 00:22:46.110
and that, you know, are bearable,

00:22:46.110 --> 00:22:48.160
you can enjoy working in that,

00:22:48.160 --> 00:22:49.200
but as you do that,

00:22:49.200 --> 00:22:51.780
carve out some space to
also be hyper idealistic

00:22:51.780 --> 00:22:52.990
and have your passions.

00:22:52.990 --> 00:22:54.240
And we're in a unique time.

00:22:54.240 --> 00:22:55.600
I mean, YouTube shows us this,

00:22:55.600 --> 00:22:57.880
my narrative shows this,
your narrative shows this,

00:22:57.880 --> 00:23:00.430
that those things will
intersect in surprising ways.

00:23:00.430 --> 00:23:02.190
There's ways to publish your passions.

00:23:02.190 --> 00:23:03.310
There's other people in the world

00:23:03.310 --> 00:23:04.700
that will also have those passions,

00:23:04.700 --> 00:23:07.490
and it can turn into a
career in and of itself.

00:23:07.490 --> 00:23:09.963
There's another question here from Ruby.

00:23:11.110 --> 00:23:12.610
- You must have faced a lot of obstacles

00:23:12.610 --> 00:23:13.780
getting to where you are today,

00:23:13.780 --> 00:23:15.900
and I'm wondering if you
ever felt like giving up.

00:23:15.900 --> 00:23:18.743
If so, how were you able to
overcome that? Thank you.

00:23:20.290 --> 00:23:22.070
- [Sal] Oh, great question.

00:23:22.070 --> 00:23:23.150
- Yeah, great question.

00:23:23.150 --> 00:23:24.830
I definitely have had hard days,

00:23:24.830 --> 00:23:27.480
and there've been moments where
I have felt like giving up,

00:23:27.480 --> 00:23:31.703
but I've often realized that if I give up,

00:23:33.940 --> 00:23:37.300
well, then I don't get to
keep doing what I love doing.

00:23:37.300 --> 00:23:39.610
And if I give up,

00:23:39.610 --> 00:23:42.560
because someone was difficult,

00:23:42.560 --> 00:23:45.000
well, then they win and
they get what they want,

00:23:45.000 --> 00:23:48.900
and I don't get to continue to
make my points of view heard.

00:23:48.900 --> 00:23:52.320
So I usually,

00:23:52.320 --> 00:23:54.030
when I have a bad day,

00:23:54.030 --> 00:23:56.710
I just call it a night
and I go to bed early,

00:23:56.710 --> 00:23:58.160
and I wake up,

00:23:58.160 --> 00:24:02.810
and most days, like, I
feel ready to do it again,

00:24:02.810 --> 00:24:05.660
and ready to revisit the situation.

00:24:05.660 --> 00:24:09.600
And I find a way to smooth
over whatever was really hard.

00:24:09.600 --> 00:24:14.600
And I encourage you just
to find something you love

00:24:14.610 --> 00:24:15.593
and stick with it.

00:24:17.480 --> 00:24:18.860
- Yeah, and I always remind folks,

00:24:18.860 --> 00:24:19.970
you know, there's no movie

00:24:19.970 --> 00:24:22.730
where the protagonist does not
have to deal with adversity.

00:24:22.730 --> 00:24:24.360
So whenever those adverse moments happen,

00:24:24.360 --> 00:24:26.100
say, "Well, this is
just part of my movie."

00:24:26.100 --> 00:24:27.870
And the movie would not be interesting

00:24:27.870 --> 00:24:28.970
without these moments.

00:24:28.970 --> 00:24:30.290
And you're absolutely right.

00:24:30.290 --> 00:24:33.000
The things that you think
are existential crises,

00:24:33.000 --> 00:24:34.600
you know, within reason,

00:24:34.600 --> 00:24:35.507
a week later, you're like,

00:24:35.507 --> 00:24:37.060
"I just have to power through it."

00:24:37.060 --> 00:24:39.710
There's ways that it can
sometimes get better,

00:24:39.710 --> 00:24:42.430
and you just have to
sometimes realize that it,

00:24:42.430 --> 00:24:44.880
you know, staying in the
game is half the battle.

00:24:45.900 --> 00:24:48.030
- Yeah, and I've had many times things

00:24:48.030 --> 00:24:49.080
didn't go the way I wanted,

00:24:49.080 --> 00:24:51.480
and many times things failed,

00:24:51.480 --> 00:24:53.730
and many times I made mistakes,

00:24:53.730 --> 00:24:54.960
and then I had to come back,

00:24:54.960 --> 00:24:57.323
and say, "Oh, I learned from that."

00:25:01.070 --> 00:25:02.090
That's how life is,

00:25:02.090 --> 00:25:06.160
and what makes you stronger
is overcoming that,

00:25:06.160 --> 00:25:08.000
and internalizing that,

00:25:08.000 --> 00:25:10.810
and saying, "Well, what
did I learn from that?

00:25:10.810 --> 00:25:13.610
And how can I change how
my life is going forward?"

00:25:13.610 --> 00:25:16.960
And if you are continuously learning,

00:25:16.960 --> 00:25:20.250
if you are having as many experiences,

00:25:20.250 --> 00:25:22.220
and then benefiting from them,

00:25:22.220 --> 00:25:24.730
and figuring out how you
can do everything better,

00:25:24.730 --> 00:25:27.790
then that all adds up.

00:25:27.790 --> 00:25:30.600
And there are a lot of
times where we're at work

00:25:30.600 --> 00:25:32.110
and people come to me
with different ideas,

00:25:32.110 --> 00:25:33.160
and be like,

00:25:33.160 --> 00:25:36.100
I'll say, "I know about doing that,

00:25:36.100 --> 00:25:38.030
'cause I did it and it didn't work."

00:25:38.030 --> 00:25:39.220
I can tell you why,

00:25:39.220 --> 00:25:41.380
'cause there are a lot of things I've done

00:25:41.380 --> 00:25:42.430
that have not worked.

00:25:43.960 --> 00:25:45.800
But I learned from it and
I'm not doing them again.

00:25:45.800 --> 00:25:47.340
And I'm actually telling other people too,

00:25:47.340 --> 00:25:49.010
like, don't do that.

00:25:49.010 --> 00:25:50.440
Sometimes I'll even say,
"Hey, you know what?

00:25:50.440 --> 00:25:51.670
You can try it, the world's different,

00:25:51.670 --> 00:25:53.550
like, maybe things have changed."

00:25:53.550 --> 00:25:58.500
And so I'm also open to how
something could be different now

00:25:58.500 --> 00:25:59.530
than it was in the past.

00:25:59.530 --> 00:26:00.363
But I tell them, like,

00:26:00.363 --> 00:26:01.800
"This is why it didn't work for me,

00:26:01.800 --> 00:26:03.990
you should take that into consideration

00:26:03.990 --> 00:26:05.740
as you consider your future plans."

00:26:07.113 --> 00:26:07.946
- You know, related to that,

00:26:07.946 --> 00:26:09.260
when people look at
you, when I look at you,

00:26:09.260 --> 00:26:10.860
you're like, oh, Susan Wojcicki,

00:26:10.860 --> 00:26:12.510
you know, titan of tech,

00:26:12.510 --> 00:26:13.680
has it all figured out,

00:26:13.680 --> 00:26:14.623
she's made it.

00:26:16.451 --> 00:26:19.600
What are the things that you feel

00:26:19.600 --> 00:26:21.860
that you feel sometimes unsure about

00:26:21.860 --> 00:26:22.743
or that you stress about?

00:26:22.743 --> 00:26:24.030
Because I think that's something that,

00:26:24.030 --> 00:26:24.870
you know, it's very easy...

00:26:24.870 --> 00:26:26.954
We all know the things we stress about,

00:26:26.954 --> 00:26:28.390
but when we look at the
Susan Wojcickis of the world,

00:26:28.390 --> 00:26:30.010
like they have it figured out.

00:26:30.010 --> 00:26:33.133
So, you know, show us that
you're like the rest of us.

00:26:34.310 --> 00:26:36.130
- Well, there are definitely...

00:26:36.130 --> 00:26:39.070
A lot of times I'm doing
things I've never done before,

00:26:39.070 --> 00:26:40.870
just because tech is in a new place

00:26:40.870 --> 00:26:42.430
that it's never been before,

00:26:42.430 --> 00:26:45.020
and we're having to figure out a lot

00:26:45.020 --> 00:26:48.090
of challenging situations
based on the size

00:26:48.090 --> 00:26:50.930
or where we are and how we can do better.

00:26:50.930 --> 00:26:55.730
And I mean, there's so
many different examples.

00:26:55.730 --> 00:26:59.060
And I mean, maybe I can just
think of like all the times

00:26:59.060 --> 00:27:01.943
that my kids have told
me how we've screwed up.

00:27:04.066 --> 00:27:06.583
And, I actually just think that,

00:27:07.910 --> 00:27:09.353
when you screw up,

00:27:11.510 --> 00:27:13.070
you should just say that,

00:27:13.070 --> 00:27:14.530
and just be honest about it.

00:27:14.530 --> 00:27:18.180
And so, you know,

00:27:18.180 --> 00:27:21.780
I look at like our Rewind video
that we did two years ago.

00:27:21.780 --> 00:27:24.913
It was the most disliked
video on the internet.

00:27:26.944 --> 00:27:28.310
- What was that?

00:27:28.310 --> 00:27:30.700
Maybe I was in under a rock someplace,

00:27:30.700 --> 00:27:32.040
but the most disliked...

00:27:32.040 --> 00:27:33.459
What is this video?
- You were under a rock.

00:27:33.459 --> 00:27:34.420
Every kid on this video,

00:27:34.420 --> 00:27:35.600
they know what I'm talking about.

00:27:35.600 --> 00:27:37.490
They know about this video,

00:27:37.490 --> 00:27:40.280
that other videos on
YouTube had taken years

00:27:40.280 --> 00:27:42.430
to have this many dislikes.

00:27:42.430 --> 00:27:45.220
And then our video, in a matter of weeks,

00:27:45.220 --> 00:27:48.020
sorry, in matter of a week, of days,

00:27:48.020 --> 00:27:50.080
it became the most disliked
video on the internet.

00:27:50.080 --> 00:27:54.240
And so I just was like,
"Yeah, the video was cringey.

00:27:54.240 --> 00:27:56.040
My kids were like, "It was cringey."

00:27:57.047 --> 00:27:58.740
I was like, "Okay, it was a cringey video.

00:27:58.740 --> 00:27:59.573
So what?

00:27:59.573 --> 00:28:00.840
We made the worst video,

00:28:00.840 --> 00:28:02.950
like the most disliked video, fine.

00:28:02.950 --> 00:28:06.477
Like, we'll make something
different next year."

00:28:06.477 --> 00:28:09.270
And so sometimes you just
got to go with, yeah,

00:28:09.270 --> 00:28:10.240
we made a mistake.

00:28:10.240 --> 00:28:11.190
Things didn't go well.

00:28:11.190 --> 00:28:12.140
So I can tell you, like,

00:28:12.140 --> 00:28:14.300
at that moment, it was not...

00:28:15.340 --> 00:28:19.600
people at YouTube were not
feeling good that the video

00:28:19.600 --> 00:28:22.943
was becoming the most disliked
video on the internet.

00:28:24.160 --> 00:28:25.330
But you learn from it.

00:28:25.330 --> 00:28:29.670
And, I think having some
humor about it too sometimes,

00:28:29.670 --> 00:28:31.690
is, you know, when you can,

00:28:31.690 --> 00:28:33.850
when it's something like that,

00:28:33.850 --> 00:28:36.487
where you can just say,

00:28:36.487 --> 00:28:38.977
"Let's just laugh and move on."

00:28:40.410 --> 00:28:41.243
- No, and I have to say,

00:28:41.243 --> 00:28:44.610
it takes an incredible
security to bring up, you know,

00:28:44.610 --> 00:28:45.620
if you asked me to bring it,

00:28:45.620 --> 00:28:46.453
and I have them,

00:28:46.453 --> 00:28:49.423
my major failures over the last
year, three years, 10 years,

00:28:50.520 --> 00:28:51.437
there's a part of my brain says,

00:28:51.437 --> 00:28:52.280
"Sal, don't bring it up.

00:28:52.280 --> 00:28:53.190
Then people are gonna know,

00:28:53.190 --> 00:28:55.210
you know, all your weaknesses."

00:28:55.210 --> 00:28:57.390
It takes a lot to bring that up,

00:28:57.390 --> 00:28:58.820
but really appreciate that.

00:28:58.820 --> 00:29:00.773
We have another question from Imani.

00:29:01.810 --> 00:29:02.790
- I was just curious,

00:29:02.790 --> 00:29:04.940
what strong women have inspired

00:29:04.940 --> 00:29:08.110
or influenced you to
become the powerful leader

00:29:08.110 --> 00:29:09.123
that you are today?

00:29:11.930 --> 00:29:14.060
- Who has inspired me?

00:29:14.060 --> 00:29:16.440
Well, many people along the way.

00:29:16.440 --> 00:29:19.860
My mom definitely inspired me.

00:29:19.860 --> 00:29:21.490
And as a kid,

00:29:21.490 --> 00:29:25.180
I was always really
impressed with Marie Curie.

00:29:25.180 --> 00:29:28.210
And she was my icon as a kid.

00:29:28.210 --> 00:29:31.940
She is someone who holds two Nobel Prizes.

00:29:31.940 --> 00:29:33.970
And I don't think there
are a lot of other people

00:29:33.970 --> 00:29:36.230
who have achieved that
in different fields.

00:29:36.230 --> 00:29:38.530
And her daughter also has a Nobel Prize,

00:29:38.530 --> 00:29:40.210
which I always thought
was really impressive.

00:29:40.210 --> 00:29:43.733
So she was one of my icons.

00:29:45.400 --> 00:29:47.370
But I would also say
that a lot of the people

00:29:47.370 --> 00:29:48.920
who mentored me

00:29:48.920 --> 00:29:52.053
and helped me get to where I am,

00:29:53.330 --> 00:29:54.310
they were not always women.

00:29:54.310 --> 00:29:55.680
In fact, most of the time they were men,

00:29:55.680 --> 00:29:57.260
because most of the people

00:29:57.260 --> 00:30:02.260
in positions above me at Google,

00:30:02.270 --> 00:30:03.900
in tech, were men.

00:30:03.900 --> 00:30:08.900
And there were a lot of super
supportive mentors that I had.

00:30:08.960 --> 00:30:11.670
And I always remind people, like,

00:30:11.670 --> 00:30:14.220
whether they're a mentee or a mentor,

00:30:14.220 --> 00:30:16.380
that anyone,

00:30:16.380 --> 00:30:17.940
like, anyone regardless
of their backgrounds,

00:30:17.940 --> 00:30:18.900
you can mentor someone.

00:30:18.900 --> 00:30:20.500
They don't have to look
like you or be like,

00:30:20.500 --> 00:30:24.430
you can just find someone who is talented

00:30:24.430 --> 00:30:25.800
that you wanna mentor,

00:30:25.800 --> 00:30:28.490
and, again, your mentors

00:30:28.490 --> 00:30:31.990
can be different from the
backgrounds you came from,

00:30:31.990 --> 00:30:34.120
and they can be really helpful to you.

00:30:34.120 --> 00:30:35.940
So I'm very thankful

00:30:35.940 --> 00:30:38.360
for all the people who
mentored me along the way,

00:30:38.360 --> 00:30:41.780
even though they came from
different backgrounds than I did,

00:30:41.780 --> 00:30:42.613
and they definitely helped me,

00:30:42.613 --> 00:30:44.310
and I definitely learned from them.

00:30:45.910 --> 00:30:47.220
- Absolutely.

00:30:47.220 --> 00:30:49.010
And you know, I know we're running low.

00:30:49.010 --> 00:30:50.153
I could talk to you for hours.

00:30:50.153 --> 00:30:51.210
There's so many questions I have

00:30:51.210 --> 00:30:53.000
about your life, about YouTube.

00:30:53.000 --> 00:30:54.920
I know we touched on
the subject of learning.

00:30:54.920 --> 00:30:57.000
Obviously Khan Academy is
very focused on learning,

00:30:57.000 --> 00:30:59.590
and YouTube has been a
big part of that journey,

00:30:59.590 --> 00:31:01.470
when I was making content for my cousins,

00:31:01.470 --> 00:31:02.720
and still do.

00:31:02.720 --> 00:31:05.360
I made three videos that I
uploaded onto YouTube yesterday,

00:31:05.360 --> 00:31:07.100
so I'm still very active there.

00:31:07.100 --> 00:31:10.080
What's your dream,

00:31:10.080 --> 00:31:13.090
if you fast forward five, 10 20 years,

00:31:13.090 --> 00:31:14.980
for, you know,

00:31:14.980 --> 00:31:16.910
I don't know if you
think in terms of legacy,

00:31:16.910 --> 00:31:18.160
but, you know, the impact

00:31:18.160 --> 00:31:19.960
that you wanna have through YouTube?

00:31:21.780 --> 00:31:24.300
- So we definitely think about YouTube

00:31:24.300 --> 00:31:26.570
and how we can continue to grow it.

00:31:26.570 --> 00:31:30.250
And I'm always just amazed
of all the new topics

00:31:30.250 --> 00:31:33.770
and new ways that we can enable voices

00:31:33.770 --> 00:31:36.110
around the world to come
and to share their story.

00:31:36.110 --> 00:31:38.040
And so part of our goal

00:31:38.040 --> 00:31:40.750
is to enable the next
generation of storytellers

00:31:40.750 --> 00:31:45.240
and to help them be able to do
that and to make a business.

00:31:45.240 --> 00:31:47.330
And the flip side of that

00:31:47.330 --> 00:31:50.690
is that we can have
incredibly compelling content

00:31:50.690 --> 00:31:54.160
for people around the world, on any topic.

00:31:54.160 --> 00:31:57.490
And so if you look at YouTube,

00:31:57.490 --> 00:31:59.820
I see that we bring many value.

00:31:59.820 --> 00:32:01.330
And of course, like, you know,

00:32:01.330 --> 00:32:06.330
enabling all the fun
videos and music videos,

00:32:06.590 --> 00:32:10.220
but we're also dealing with a
lot of really important topics

00:32:10.220 --> 00:32:12.383
that just were not talked about before,

00:32:13.300 --> 00:32:16.580
whether that involves
mental health issues,

00:32:16.580 --> 00:32:19.450
or hearing from people
of different backgrounds

00:32:19.450 --> 00:32:23.210
that never were represented
on media traditionally,

00:32:23.210 --> 00:32:24.930
like, those are really compelling

00:32:24.930 --> 00:32:26.663
and important points of view.

00:32:27.629 --> 00:32:28.600
- You know, one last question,

00:32:28.600 --> 00:32:30.530
it feels like there's two competing winds.

00:32:30.530 --> 00:32:35.300
There is one wind where there's
more tools and resources,

00:32:35.300 --> 00:32:37.170
YouTube, Khan Academy, you know,

00:32:37.170 --> 00:32:39.210
all the other things that Google provides,

00:32:39.210 --> 00:32:41.730
that are enabling the
individual to publish,

00:32:41.730 --> 00:32:42.760
to express themselves,

00:32:42.760 --> 00:32:45.200
to discover points of view, to learn.

00:32:45.200 --> 00:32:46.840
It really does feel like
we're an inflection point,

00:32:46.840 --> 00:32:50.000
a renaissance, so to
speak, in human society.

00:32:50.000 --> 00:32:51.600
On the other side,

00:32:51.600 --> 00:32:54.000
there are reasons why
people can get cynical.

00:32:54.000 --> 00:32:55.760
It feels like we are more polarized

00:32:55.760 --> 00:32:57.550
as a country or as a world.

00:32:57.550 --> 00:33:00.550
It feels like, you know,
inequity is growing.

00:33:00.550 --> 00:33:03.180
It feels like people aren't
listening to each other anymore.

00:33:03.180 --> 00:33:05.370
You know, the climate's in trouble.

00:33:05.370 --> 00:33:07.670
If there's a young person watching...

00:33:07.670 --> 00:33:09.370
And there's a pandemic,

00:33:09.370 --> 00:33:12.300
and people are feeling
isolated and lonely.

00:33:12.300 --> 00:33:14.820
What message can you give to someone

00:33:14.820 --> 00:33:18.230
who's kind of trying to
navigate these two currents?

00:33:18.230 --> 00:33:21.320
- YouTube does enable people

00:33:21.320 --> 00:33:23.190
to connect with each other as humans.

00:33:23.190 --> 00:33:24.670
And there's something very human

00:33:24.670 --> 00:33:27.960
about the fact that people
are, a lot of times,

00:33:27.960 --> 00:33:30.680
going to YouTube and
talking about how they feel,

00:33:30.680 --> 00:33:33.880
what their deepest challenges were,

00:33:33.880 --> 00:33:35.690
about diseases they have,

00:33:35.690 --> 00:33:38.070
and there's something really cathartic

00:33:38.070 --> 00:33:40.730
about people going and
sharing the challenges

00:33:40.730 --> 00:33:41.563
that they have.

00:33:41.563 --> 00:33:44.970
And we've seen other people
really be able to relate

00:33:44.970 --> 00:33:45.980
and benefit from that.

00:33:45.980 --> 00:33:48.460
So I do see a human connection

00:33:48.460 --> 00:33:50.290
that's incredibly powerful on YouTube

00:33:50.290 --> 00:33:52.890
for us to understand each
other more as humans.

00:33:52.890 --> 00:33:57.390
And I've also seen that
there's an incredible amount

00:33:57.390 --> 00:33:58.430
of good that comes,

00:33:58.430 --> 00:34:03.430
whether it's something
like the 20 million trees

00:34:05.830 --> 00:34:10.560
that are being planted
and organized on YouTube,

00:34:10.560 --> 00:34:14.470
or fundraisers to support
people during hard times.

00:34:14.470 --> 00:34:18.150
And so I do see that YouTube

00:34:18.150 --> 00:34:21.490
can be used for all of
kinds of good outcomes.

00:34:21.490 --> 00:34:24.670
And I encourage you to use

00:34:24.670 --> 00:34:27.040
like YouTube and all social platforms,

00:34:27.040 --> 00:34:28.670
if there's a cause you believe in,

00:34:28.670 --> 00:34:30.080
you can make a difference,

00:34:30.080 --> 00:34:31.300
you can make a video,

00:34:31.300 --> 00:34:33.050
you can organize groups,

00:34:33.050 --> 00:34:35.800
and I encourage you to speak your voice,

00:34:35.800 --> 00:34:39.560
and now's the best time
ever to be able to do that.

00:34:39.560 --> 00:34:42.870
So I encourage you to do what's important

00:34:42.870 --> 00:34:44.613
for you and to speak up.

00:34:46.329 --> 00:34:49.420
- No, thank you so much
for that. I'm inspired.

00:34:49.420 --> 00:34:51.728
I'm gonna go use social media

00:34:51.728 --> 00:34:53.850
to try to change the world.

00:34:53.850 --> 00:34:55.060
Well, Susan, thank you so much.

00:34:55.060 --> 00:34:56.530
I know you're incredibly busy.

00:34:56.530 --> 00:34:58.540
And thank you for making
the time out for all of us,

00:34:58.540 --> 00:34:59.830
and all of the students who are watching,

00:34:59.830 --> 00:35:01.300
and their questions.

00:35:01.300 --> 00:35:05.980
And, you know, I'm excited
to be part of your journey,

00:35:05.980 --> 00:35:09.250
which you are empowering Khan
Academy on so many levels,

00:35:09.250 --> 00:35:12.410
and see where we can take the world.

00:35:12.410 --> 00:35:13.640
- Well, thank you.

00:35:13.640 --> 00:35:16.630
And I'm glad we have been
part of your journey too.

00:35:16.630 --> 00:35:18.170
- Well, thanks everyone for joining.

00:35:18.170 --> 00:35:19.370
As you could tell,

00:35:19.370 --> 00:35:20.900
you know, these conversations,

00:35:20.900 --> 00:35:22.430
when you have a guest like Susan,

00:35:22.430 --> 00:35:23.770
I could talk for hours,

00:35:23.770 --> 00:35:25.280
so much to learn from,

00:35:25.280 --> 00:35:27.130
and I find her to be incredibly inspiring.

00:35:27.130 --> 00:35:29.300
And you know, I've known
Susan and her family

00:35:29.300 --> 00:35:31.460
for many years now.

00:35:31.460 --> 00:35:34.230
And you know, every time I chat,

00:35:34.230 --> 00:35:35.550
I never cease to be impressed

00:35:35.550 --> 00:35:37.610
by what, actually, her and her sisters

00:35:37.610 --> 00:35:40.750
and her mother are accomplishing
on a regular basis.

00:35:40.750 --> 00:35:42.543
So I thank you all for joining.

00:35:43.593 --> 00:35:44.980
We're actually going to have...

00:35:44.980 --> 00:35:46.540
Our next show is March 10th.

00:35:46.540 --> 00:35:48.050
The guest is Mark Sternberg.

00:35:48.050 --> 00:35:49.510
It'll actually be hosted

00:35:49.510 --> 00:35:54.510
by Khan Academy's Chief Learning
Officer, Kristen DiCerbo.

00:35:54.530 --> 00:35:55.810
And they're going to be talking...

00:35:55.810 --> 00:35:59.230
This is Mark Sternberg from
the Walton Family Foundation,

00:35:59.230 --> 00:36:00.840
and we'll talk about philanthropy

00:36:00.840 --> 00:36:02.870
and learning and impact on education.

00:36:02.870 --> 00:36:06.070
So I look forward to
seeing all of y'all there.

00:36:06.070 --> 00:36:08.053
Have a good weekend.

00:36:09.157 --> 00:36:11.740
(bright music)