Question

How do you use the chain rule to differentiate `y=tan^4x`?

Answer 1

`4tan^3 x sec^2 x`

Explanation:

let tan x = t, so that `tan^4 x = t^4`

Thus `d/dx tan^4 x= d/dt t^4 dt/dx`

`4t^3 d/dx tan x`

=`4tan^3 x sec^2 x`