lim/x→1/[(x^3-3x^2+2)/(x^3-x^2-x+1)]是lim(0/0)模型
∴由洛必达法则得原式=lim/x→1/[(3x^2-6x)/(3x^2-2x-1)]=lim/x→1/[3x(x-2)/(x-1)(3x+1)]
因为分子不为0,分母趋近于0,∴原式=∞