∫arctg√x dx
= x arctg√x - ∫x darctg√x
= x arctg√x - ∫x/(1+x) d√x
= x arctg√x - ∫1 - 1/(1+x) d√x
= x arctg√x - √x + ∫1/(1+x) d√x
= x arctg√x - √x + arctg√x
= （x+1） arctg√x - √x