# Thread: Finding Values of x

1. ## Finding Values of x

1)For what values of x is the graph of y=e^-x^2 concave down?

I am not sure how to go about doing this problem, so please, any advice or steps on how to complete the problem will be much appreciated.

-M

2. Originally Posted by blurain
1)For what values of x is the graph of y=e^-x^2 concave down?

I am not sure how to go about doing this problem, so please, any advice or steps on how to complete the problem will be much appreciated.

-M
Find the second derivative and set it equal to zero. Solve for all values of x and test in between those values to see if you get a negative or positive number. Negative results mean it is concave down within that sub-domain.

3. I'm not sure how to find the derivative of y=e^-x^2?

4. Originally Posted by blurain
I'm not sure how to find the derivative of y=e^-x^2?
Chain Rule..
$f(x)=e^{g(x)}$
$f'(x)=g'(x)e^{g(x)}$