Question

Find the anti derivative for 4/(x^2+1)

Answer 1

4 (x^2 + 1)^-1

4 * -1 * (x^2 + 1)^-2 * 2x

-8x / (x^2+1)^2

Answer 2

Your question is of this type:

Integral of du / (a^2 + u^2) = (1/a) tan-1(u/a) +c

Answer 3

OOPS... missed the "anti" part

that is the derivative