∫f(x)=x²lnxf(x)=lnx*2x+x²*1/x=2xlnx+x∫xf(x) dx=∫x*(2xlnx+x) dx=2∫lnx d(x³/3) + ∫x² dx=(2/3)x³lnx - (2/3)∫x² dx + ∫x² dx,分部积分法=(2/3)x³lnx + (1-2/3)*x...