Use the identities to find the values of the sine and cosine functions for the following angle measure (theta) if cos2(theta) = 12/13. Find sine(theta) and cosine(theta).

Answer 1

You need 2 identities here

sin² + cos² = 1 and cos 2x = cos²x - sin²x

from these you can get cos x = sqrt((1+cos 2x)/2) and sin x = sqrt((1-cos 2x)/2)

and that will allow you to solve the problem