∫arctan√x dx
=xarctan√x-∫xd(arctan√x)
=xarctan√x-∫x*1/(1+x)dx
=xarctan√x-∫(1-1/(1+x))dx
=xarctan√x-x+ln(1+x)+C
∫x²/√(1-x²﹚dx x=sint 0