当a[f(x1)]min
f'(x)=1-(a+1)/x+a/x^2=(x-a)(x-1)/x^2
a0,g'(0)=1/2>0
故有[g(x2)]min=g'(0)=1/2
故有1/2>e-(a+1)-a/e
1/2+1-e>-(a+a/e)
a(1+1/e)>e-3/2
a>(e^2-3/2e)/(e+1)
即范围是a>(e^2-3/2e)/(e+1)
当a[f(x1)]min
f'(x)=1-(a+1)/x+a/x^2=(x-a)(x-1)/x^2
a0,g'(0)=1/2>0
故有[g(x2)]min=g'(0)=1/2
故有1/2>e-(a+1)-a/e
1/2+1-e>-(a+a/e)
a(1+1/e)>e-3/2
a>(e^2-3/2e)/(e+1)
即范围是a>(e^2-3/2e)/(e+1)