∫ (sin√x)/√x dx
= ∫ 2(sin√x)/(2√x) dx
= 2∫ sin√x d(√x),d(√x) = 1/(2√x) dx
= 2 · (- cos√x) + C
= - 2cos√x,用换元u = √x做也可以,不过这个很简单而已