Question

Can you help me prove the following identity please?

Answer 1

I think it would be easier to do LHS no?

Answer 2

recall what sin^2(theta)=1/2(1-cos2(theta)), there is one similar to for cos^2(theta)

Answer 3

Yes, thats the first pythagorean identity if im not wrong

Answer 4

so for cos² theta, it would be 1-sin²theta

Answer 5

actually it the same as for sin^2(theta) except its +cos2(theta)