已知函数f(x)=3ax^4-2(3x+1)x^2+4x,当a=1/6时,求f(x)的极值
问题描述:
已知函数f(x)=3ax^4-2(3x+1)x^2+4x,当a=1/6时,求f(x)的极值
答
应该是f(x)=3ax^4-2(3a+1)x^2+4xa=1/6f(x)=x^4/2-3x²+4xf'(x)=2x³-6x+4=0x³-3x+2=0(x³-1)-3x+3=0(x-1)(x²+x+1)-3(x-1)=0(x-1)(x²+x-2)=0(x-1)²(x+2)=0x=1,x=-2f'(x)>=0时...