- #1
lase
- 22
- 0
Homework Statement
Find f'(x) for f(x) = sin x + 2 cos^3 x
Homework Equations
Other than basic derivative properties and formulas, no.
The Attempt at a Solution
f'(x) = sin x + 2cos^3 x
= cos x - 6sin^2 x
The book says the answer is f'(x) = cos x - 6cos^2 x sin x however I don't understand where the sin x comes from... any help?