答
f'(x)=3x^2-3=3(x+1)(x-1) f(X)在x=1取极小值
要使函数在开区间(a,6-a^2)上有最小值,则x=1必须包含于(a,6-a^2)有:
a答案是【-2,1)x=1时,f(x)min=-2.f(x)=x^3-3x=-2时x^3-3x+2=0x³-x-2x+2=0x(x²-1)-2x+2=0x(x+1)(x-1)-2(x-1)=0(x²+x)(x-1)-2(x-1)=0(x-1)(x²+x-2)=0(x-1)(x+2)(x-1)=0(x-1)²(x+2)=0x=1,x=-2∴-2