- #1
chudzoik
- 14
- 0
Homework Statement
f(x) = cos2x - sin2x
The Attempt at a Solution
f'(x) = (2cosx)(-sinx) - (2sinx)(cosx)
f'(x) = -2cosxsinx - 2sinxcosx
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.