∫1x3+1dx=13∫(1x+1−x−2x2−x+1)dx =13∫[1x+1−2x−12(x2−x+1)+32(x2−x+1)]dx =13∫[1x+1−2x−12(x2−x+1)+32.1(x−12)2+34]dx 13[ln|x+1|−12ln(x2−x+1)+√3arctan(2x−1√3)]+C
∫1x3+1dx=13∫(1x+1−x−2x2−x+1)dx =13∫[1x+1−2x−12(x2−x+1)+32(x2−x+1)]dx =13∫[1x+1−2x−12(x2−x+1)+32.1(x−12)2+34]dx $
=\frac{1}{3}[ln|x+1|-\frac{1}{2}ln(x^2-x+1)+\sqrt{3}arctan(\frac{2x-1}{\sqrt{3}})]+C$