已知f(x)=(-1/3)x^3+2ax^2-3(a^2)x+b(0

f'(x)＝－x^2＋4ax－3a^2＝－(x-a)(x-3a),令f'(x)＝0,得x＝a或3a x＜a时,f'(x)＜0,f(x)单调减少 a＜x＜3a时,f'(x)＞0,f(x)单调增加 x＞3a时,f'(x)＜0,f(x)单调减少 所以,f(x)的单调增加区间是[a,3a],单调减少区间是(...