Question

求函数f（x）=x^2e^-x的极值

Answer 1

f'(x)=(2x-x^2)e^(-x)=0

有：x=0,2

f''(x)=(x^2-4x+2)e^(-x)

x=0时,f''(x)=2>0

x=2,f''(x)=-2e^(-2)