Question

Write the expression as the sine, cosine, or tangent of an angle.

cos 96° cos 15° + sin 96° sin 15°

Answer 1

Take a look at the sum identities

Answer 2

cos(x-y)=cos x coy y +sin x sin y?

Answer 3

@Xavier

Answer 4

Yup

Answer 5

I cant understand how to plug that in though...

Answer 6

Your expression is the same as the identity you just posted
cos x coy y +sin x sin y = cos(x-y)
Substiutute for x and y

Answer 7

well thats what I mean, what is the x and y? cos x and sin x?

Answer 8

cos x cos y +sin x sin y
cos 96° cos 15° + sin 96° sin 15°

Answer 9

cos(x-y)
cos(96-15)
cos (81)?

Answer 10

@Xavier

Answer 11

Yes that's correct. Don't forget the degree symbol