设√（5-4x）是t x=(5-t^2)/4 dx=-1/2tdt
∫x/（√（5-4x））dx
=∫(5-t^2)/4t*(-1/2t)dt
=∫(t^2-5)/8dt
=∫t^2/8dt-∫5/8dt
=1/24*t^3-5/8*t+c
=1/24*(√(5-4x))^3-5/8*√(5-4x)+c
设√（5-4x）是t x=(5-t^2)/4 dx=-1/2tdt
∫x/（√（5-4x））dx
=∫(5-t^2)/4t*(-1/2t)dt
=∫(t^2-5)/8dt
=∫t^2/8dt-∫5/8dt
=1/24*t^3-5/8*t+c
=1/24*(√(5-4x))^3-5/8*√(5-4x)+c