令F’(x)=(x^2-2)e^x＝0==>x=±√2
F”(x)=(2x+x^2-2)e^x,F”(-√2)=(-2√2)e^（-√2）0
∴f(x)在x=-√2处取极大值,在 x=√2处取极小值
x∈(-∞,- √2)时,函数f(x)单调增,x∈[-√2,√2)时,函数f(x)单调减；x∈[√2+∞)时,函数f(x)单调增.