Question

What is the derivative of `y=sec^2(x)`?

Answer 1

We need to use the chain rule

`y=sec^2(x)`

Let `u=sec(x)`

`u'=sec(x)tan(x)`

`y=u^2`

`y'=2u*u'`

`y'=2sec(x)* sec(x)tan(x)=2sec^2(x)tan(x)`