# How do you differentiate #f(x)=cos(x^3)#?

##### 2 Answers

#### Explanation:

Use chain rule:

Then

So

The answer is

#### Explanation:

I mainly use formulas because some of them are easy to memorize and they help you see the answer right away, but you can also use the "u substitution." I think that's what is officially known as the "Chain Rule"

Note that

Our problem

Since it's not simply

Another method: "u substitution"

Let's say

And the derivative of

Substitute back

Hope this helps :)