# Thread: Another derivative problem

1. ## Another derivative problem

I'm so lost

2. Originally Posted by lyzzi3
I'm so lost
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?

3. Originally Posted by lyzzi3
I'm so lost
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