f(x) = -x^3 + 12xf'(x) = -3x^2 + 12 = -3(x+2)(x-2)x＜-2,或x＞2时,f'(x)＜0,f(x)单调减-2＜x＜2时,f'(x)＞0,f(x)单调增单调减区间（-∞,-2）,（2,+∞）单调增区间（-2,2）x=-2时有极小值：f(-2) = -(-2)^3+12*(-2...