=x（lnx）²-∫x（2lnx）/xdx
=x（lnx）²-2∫lnxdx
=x（lnx）²-2xlnx+2∫x*（1/x）dx
=x（lnx）²-2xlnx+2能用不定積分的換元法解么？最后一步錯了，應(yīng)為x（lnx）²-2xlnx+2 x+C換元法的話如下：令lnx=t，則x=e^t原式=∫t²de^t=t²e^t-∫e^t*2tdt=t²e^t-2∫tde^t=t²e^t-2te^t+2∫e^tdt=t²e^t-2te^t+2e^t+C=x（lnx）²-2xlnx+2x+C