求不定积分：x*ln(1+x)dx - 知识问答

求不定积分：x*ln(1+x)dx

1个回答

原式=1/2∫ln(x+1)dx²
=1/2*x²ln(x+1)-1/2∫x²dln(x+1)
=1/2*x²ln(x+1)-1/2∫x²/(x+1) dx
=1/2*x²ln(x+1)-1/2∫(x²-1+1)/(x+1) dx
=1/2*x²ln(x+1)-1/2∫[x-1+1/(x+1)] dx
=1/2*x²ln(x+1)-1/4*x²+1/2x-1/2ln(x+1)+C

相关问题