设u(x)=4x^3-9x^2+6x,则[u(x)]^=12x^2-18x+6=6(2x-1)(x-1）,y^={y[u(x)]}^*[u(x)]^＝-[1/（4x^3-9x^2+6x）^2]*6(2x-1)(x-1）,＝-[6(2x-1)(x-1)]/（4x^3-9x^2+6x）^2.依据复合函数的求导法则