A ∫(上标是+∞,下标是1)sinxdx B ∫(上标是+∞,下标是1)1/x^(1/2)dxC ∫(上标是+∞,下标是1)1/[ [x*(x^(1/2))] ^(1/2)]dx D ∫(上标是+∞,下标是1)1/[x* x^(1/2)]dx
哈,好的好的,那A 怎么判断哦?