∫2x+tan−1x1+x2dx=
log(1+x2)
log(1+x2)+tan−1x32+C
log(1+x2)+cot−1x32+C
log(1+x2)+23tan−1x32+C
I=∫2x+tan−1x1+x2dxI=∫2x1+x2dx+∫tan−1x1+x2dx=∫2x1+x2dx+∫tdt ∵tan−1x=t,11+x2dx=dt=log1+x2+23t32+C=log1+x2+23tan−1x32+C