∫√1+x2x4dx
Let I=∫√1+x2x4dx=∫√1+x2x.1x3dx=∫√1+x2x2.1x3dx=∫√1x2+1.1x3dxPut 1+1x2=t2⇒−2x3dx=2tdt⇒−1x3=tdt∴ I=−∫t2dt=−t33+C=−13(1+1x2)3/2+C