分部积分啦!∫xlnx/[(1+x^2)^2]dx=(-1/2)∫lnxd(1/(1+x^2))=(-1/2)lnx/(1+x^2)+(1/2)∫1/[(1+x^2)*x]dx=(-1/2)lnx/(1+x^2)+(1/2)∫x/[(1+x^2)*x^2]dx=(-1/2)lnx/(1+x^2)+(1/4)∫1/[(1+x^2)*x^2]d(x^2)=(-1/2)lnx/(1+...