u=ln(x^2 + 1)-----)du=2x/(x^2+1)
v=x--------------)dv= dx.
note: der( u*v) = u dv+ v du.
and then Integrate both sides and you get :
uv= int(u dv)+ int (v du). Switch it around and you get int(u dv) =uv- int (v du)
So the integral is ln(x^2 + 1)*x- int(2x^2/x^2+1)
Next, integrate the...