∫dx/x^2(x^2+1)
=∫dx*[1/x^2-1/(x^2+1)]
=∫dx/x^2-∫dx/(x^2+1)
=-1/x-arctanx+C不好意思 应该是1/[x²（x²+1）]就是你那个问题的解法那中间怎么会有减的啊？我晕，你不会约分算嘛1/x^2-1/(x^2+1)=(x^2+1-x^2)/x^2(x^2+1)=1/x^2(x^2+1)