# Another derivative problem

• Mar 25th 2008, 06:33 PM
lyzzi3
Another derivative problem
I'm so lost (Doh)
• Mar 25th 2008, 06:58 PM
mr fantastic
Quote:

Originally Posted by lyzzi3
I'm so lost (Doh)

You have nested chain rules.

Start off by letting $u = x^5$ and use the chain rule.

To get the derivative of $\cos (\cos u)$ with respect to u, let $w = \cos u$.

And you know how to differentiate $\cos w$ with respect to w, right?
• Mar 26th 2008, 04:29 AM
topsquark
Quote:

Originally Posted by lyzzi3
I'm so lost (Doh)

You have asked at least six questions of this kind. You would do well to talk to your instructor and see if they can help you learn this material better.

-Dan