Question

不定积分x的立方/1＋X的平方

Answer 1

∫x^3/(1+x^2)dx
=1/2∫x^2/(1+x^2)dx^2
=1/2∫(x^2+1-1)/(1+x^2)dx^2
=1/2∫[1-1/(1+x^2)]dx^2
=1/2x^2-1/2ln(1+x^2)+C