y=(x²+1)(3x-1)(1-x³)取自然对数,则lny=ln(x²+1)+ln(3x-1)+ln(1-x³)对x求导,则(1/y)y'=2x/(x²+1)+3/(3x-1)-3x²/(1-x³)则y'=y[2x/(x²+1)+3/(3x-1)-3x²/(1-x³)]=[(x²+1)(3x-1)(1-x³)][2x/(x²+1)+3/(3x-1)-3x²/(1-x³)]
ln³x'=(3ln²x)×(1/x)=3ln²x/x