原式=1/2∫ln²xdx²
=1/2*x²ln²x-1/2∫x²dln²x
=1/2*x²ln²x-1/2∫x²*2lnx*1/xdx
=1/2*x²ln²x-1/2∫lnxdx²
=1/2*x²ln²x-1/2*x²lnx-1/2∫x²dlnx
=1/2*x²ln²x-1/2*x²lnx-1/2∫x²*1/xdx
=1/2*x²ln²x-1/2*x²lnx-1/2∫xdx
=1/2*x²ln²x-1/2*x²lnx-1/4*x²+C
原式=1/2∫ln²xdx²
=1/2*x²ln²x-1/2∫x²dln²x
=1/2*x²ln²x-1/2∫x²*2lnx*1/xdx
=1/2*x²ln²x-1/2∫lnxdx²
=1/2*x²ln²x-1/2*x²lnx-1/2∫x²dlnx
=1/2*x²ln²x-1/2*x²lnx-1/2∫x²*1/xdx
=1/2*x²ln²x-1/2*x²lnx-1/2∫xdx
=1/2*x²ln²x-1/2*x²lnx-1/4*x²+C