f(x)=x^3-12x+8?!
f'(x)=3x^2-12
令f'(x)=0
x=2或x=-2
则f(x)在x∈(-2,2)递减,x∈(-无穷,-2)和(2,无穷)递增
f(-3)=17;f(-2)=24;f(2)=-8;f(3)=-1
M=24,m=-8
M-m=32
f(x)=x^3-12x+8?!
f'(x)=3x^2-12
令f'(x)=0
x=2或x=-2
则f(x)在x∈(-2,2)递减,x∈(-无穷,-2)和(2,无穷)递增
f(-3)=17;f(-2)=24;f(2)=-8;f(3)=-1
M=24,m=-8
M-m=32