Question

What is `cos^4theta-sin^2theta` in terms of non-exponential trigonometric functions?

Answer 1

f(x) = (cos 2x + 1 - sin x)(cos 2x + 1 + sin x

Explanation:

`f(x) = (cos^4 x - sin ^2 x) = (cos^2 x - sin x)(cos^2 x + sin x)`
Replace `cos^2 x` by (cos 2x + 1)

f(x) = (cos 2x + 1 - sin x)(cos 2x + 1 + sin x)