答：f是积分号吧?设t=√x,dx=d(t^2)=2tdt∫ [ (x^(3/2) ] /(1+x) dx=∫ (t^3) /(1+t^2) *2t dt= 2 ∫ (t^4) /(1+t^2) dt=2 ∫ (t^2+1-1)^2 /(1+t^2) dt=2 ∫ (1+t^2) -2 +1/(1+t^2) dt=2 ∫ (t^2-1) +1/(1+t^2) dt=(...