# Homework Help: Chain Rule

1. Jul 31, 2010

### delfam

1. The problem statement, all variables and given/known data

(cos^3)(e^4(theta))

2. Relevant equations
f(x)=f(g(x))

3. The attempt at a solution
u=e^49theta))

-3sin^2(e^4(theta)) x e^4(theta)

Just not sure what I'm doing wrong, I know what the answer is I'm just not sure how to get to it.

2. Jul 31, 2010

For starters, you need to be clearer. Is your problem $$cos(e^4\theta)^3$$ ? It's hard to tell from the way you wrote it. If it is, then you need to use the chain rule, which is:

$$[f( g(x) )] ' = f'(g(x)) * g'(x).$$

3. Jul 31, 2010

The typical way to recall the steps if you're having trouble is:

1. derivative of the outside function, leaving the inside function untouched.
2. multiply by the derivative of the inside function.

4. Jul 31, 2010

### delfam

the question is cos^3 * e^4theta the theta is connected to the raised power of 4.

5. Jul 31, 2010