原式=∫(x^5+1-1)/(x+1)·dx=∫(x^5+1)/(x+1)·dx-∫1/(x+1)·dx=∫(x^4-x^3+x^2-x+1)dx-ln|x+1|=1/5·x^5-1/4·x^4+1/3·x^3-1/2·x^2+x-ln|x+1|+C
