f(x)=ax^3/3-3X^2/2+(a+1)x+1若导函数>X^2-x-a+1对a>0恒成立求x范围
x²-x-a+1对a>0恒成立即:ax²-3x+a+1>x²-x-a+1a(x²+2)>x²+2x则:(x"}}}'>