`intxtan^-1xdx`

Explanation

`intxtan^-1xdx`
[`tan^-1x`=1st function
x=2nd function]
=`tan^-1x.x^2/2-int1/(1+x^2) .x^2/2dx` =`x^2/2tan^-1x-1/2x+1/2tan^-1x+C`
(x^2+1)/2 tan^-1x-x/2+C`