Question

What is `int (x^2-1)/(x^2+1)dx`?

Answer 1

`x-2tan^-1 x +C`

Explanation:

`int(x^2-1)/(x^2+1) dx = int (x^2+1-1-1)/(x^2+1) dx`

`= int (1-2/(x^2+1)) dx`

`= x-2tan^-1 x +C`