f(x)=x^3-3x^2-9x-5,试确定f(x)的单调区间,极值,凹向和拐点
问题描述：
f(x)=x^3-3x^2-9x-5,试确定f(x)的单调区间,极值,凹向和拐点
答
f(x)=x^3-3x^2-9x-5f'(x)=3x^2-6x-9=3(x+2)(x-3)f''(x)=6x-6单调区间：x＜-2和x＞3时,f'(x)＞0,单调增-2＜x＜3是,f'(x)＜0,单调减即：区间（-∞,-2）,单调增区间（-2,3）,单调减区间（3,+∞）,单调增x=-2和x=3时,f'(...