令√x=t，则原式=∫(t+1)(t^2-1)/t*2tdt=2∫(t^3+t^2-t-1)dt=1/2t^4+2/3t^3-t^2-2t+C=1/2x^2+2/3x^(3/2)-x-2x^(1/2)+C
