用分布积分求∫xln(x-1)dx

1个回答

  • OK

    ∫udv=uv-∫vdu知道吧

    这里:udv=xdx,v=(1/2)x^2

    所以:原式=[(1/2)x^2]ln(x-1)-(1/2)∫(x^2dln(x-1)

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

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

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

    =[(1/2)x^2]ln(x-1)-(1/4)(x+1)^2+ln(x-1)

    敲了半天,能采纳?