f(X)=x^3+mx^2-m^2x+1,有极大值9,求m
问题描述:
f(X)=x^3+mx^2-m^2x+1,有极大值9,求m
答
求导:
f'(x)=3x^2+2mx-m^2=0
解得x=m/3或-m
又f''(x)=6x+2m