Question

∫1/x(1+x^2 ) ⅆx

Answer 1

use partial fractions:
A/x + B/(1+x^2) = 1

Answer 2

A + Ax^2 + Bx = 1
.... hmmm doesnt work does it

Answer 3

wait lets try again:

\[\int\limits_{}^{}1/[x(1+x^2)]dx = \int\limits_{}^{}xdx/[x^2(1+x^2)]\]
Let u = x^2, du= 2x dx