Question

Question #360f2

Answer 1

See below.

Explanation:

I assume that you are trying to prove that `cos^2x-sin^2x=1-2sin^2x`. If so, here is the proof.

We know that `cos^2x+sin^2x=1`, so `cos^2x=1-sin^2x`

Plugging this into the `cos^2x`, we get that:

`cos^2x-sin^2x=1-sin^2x-sin^2x=1-2sin^2x`