f(x)
= e^x/x ; x>0
= e^(-x)/x ; x<0
x=0 , f(x) 没有定义
x>0
f'(x) = e^x/x - e^x/x^2
f'(x)= 0
x-1 =0
x=1 (min)
x<0
f'(x) = -e^(-x)/x - e^(-x)/x^2
f'(x)= 0
x+1 =0
x=-1 (max)
ans : A
窝囊废