Question

What is the derivative of `f(x)=tan(cosx))`?

Answer 1

`f'(x)=-sin(x)sec^2(cos(x))`

Explanation:

Use Chain Rule.

`f'(x)=sec^2(cos(x))d/dx[cos(x)]`

`f'(x)=-sin(x)sec^2(cos(x))`