计算不定积分x+(arctanx)²/1+x² dx 如图

∫{[x+arctanx)^2]/(1+x^2)}dx=∫[x/(1+x^2)]dx+∫(arctanx)^2/(1+x^2)]dx
=(1/2)ln(1+x^2)+(1/3)(arctanx)^3+c