Question

How do you find the antiderivative of `secx / (1+tan^2x)`?

Answer 1

Maybe with this kind of notation you will realize this integral is very simple :`int(sec(x))/(1+tan^2(x))dx = 1/cos(x)*1/(1+tan^2(x))dx`

`(1+tan^2(x))^(-1)=cos^2(x)`

Then `int cos(x) dx`

`= [sin(x)]+C`