- #1

chudzoik

- 14

- 0

## Homework Statement

f(x) = cos

^{2}

*x*- sin

^{2}

*x*

## The Attempt at a Solution

f'(x) = (2cos

*x*)(-sin

*x*) - (2sin

*x*)(cos

*x*)

f'(x) = -2cos

*x*sin

*x*- 2sin

*x*cos

*x*

This is what I think the answer should be, but the back of the book says otherwise. I need help identifying what I did wrong.