# Math

Derive this identity from the sum and difference formulas for cosine:
sinasinb=1/2[cos(a-b)cos(a+b)]
Start with the right-hand side since it is more complex.
Calculations:
_____
_____
_____
Reason:
_____
_____
_____

1. 👍
2. 👎
3. 👁
4. ℹ️
5. 🚩
1. look at the end of your last post of this same thing
https://www.jiskha.com/display.cgi?id=1527528235

1. 👍
2. 👎
3. ℹ️
4. 🚩

## Similar Questions

1. ### Algebra 2

Which cosine function has maximum of 4, a minimum of -4, and a period of 2pi/3? A. y=4 cos 3 theta B. y= 4 cos 2 theta/3 C. y=4 cos theta/3 D. y=4 cos 3 theta

2. ### algebra

A certain cosine function completes 6 cycles over the interval [0,2π]. Which function rule could model this situation? f(x)=cos(1/6x) f(x)=cos(x)+6 f(x)=cos(6x) f(x)=6cos(x)

3. ### TRIG/ALGEBRA

1) Find the exact value. Use a sum or difference identity. tan (-15 degrees) 2) Rewrite the following expression as a trigonometric function of a single angle measure. cos 3x cos 4x - sin 3x sine 4x

4. ### self-study calculus

Sketch the curve with the given vector equation. Indicate with an arrow the direction in which t increases. r(t)=cos(t)I -cos(t)j+sin(t)k I don't know what to do. I let x=cos(t), y=-cos(t) and z= sin(t). Should I let t be any

1. ### Trigonometry

How could you evaluate tan (13pi/12) if you did not know the sum and difference formula for tangent? Would you use the sin and cos sum and difference formulas, and if so, can someone walk me through it? Thank you!!!

2. ### Algebra 2 Honors

Find the exact value by using an appropriate sum or difference identity. cos(165) degrees

3. ### Trigonometry

Use a sum of difference identity to write the expression as a single function theta: cos(theta - pi). Okay so I know we will use cosAcosA+sinBsinB I got: cos(theta)cos(theta)sin(pi)sin(pi) I don't know how to solve from here and

4. ### algebra

A certain cosine function completes 6 cycles over the interval [0,2π]. Which function rule could model this situation? f(x)=cos(16x) f(x)=cos(x)+6 f(x)=cos(6x) f(x)=6cos(x)

1. ### Trigonometry

Express each of the following in terms of the cosine of another angle between 0 degrees and 180 degrees: a) cos 20 degrees b) cos 85 degrees c) cos 32 degrees d) cos 95 degrees e) cos 147 degrees f) cos 106 degrees My answer: a) -

2. ### Math 2nd question

Express as a single sine or cosine function (note: this is using double angle formulas) g) 8sin^2x-4 I just don't get this one. I know it's got something to do with the 1-2sin^2x double angle formula. It's the opposite though? :S

3. ### Trig

Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < 2pi Find: sin (v + u) cos (v - u) tan (v + u) First compute or list the cosine and sine of both u and v. Then use the combination rules sin (v + u) = sin u cos v + cos v

4. ### Trigonometry

Use the power-reducing formulas to rewrite the expression in terms of the first power of the cosine. [#1.] (sin^4x)(cos^4x) [#2.] (sin^4x)(cos^2x)