设F(x)=f(x)/e^x,则
F'(x)=[f'(x)e^x-f(x)e^x]/e^(2x)=[f'(x)-f(x)]/e^x>0
所以,F(x)单增
所以,F(a)>F(0)
即f(a)/e^a>f(0)
所以,f(a)>e^af(0)
设g(a)=alne-elna=a-elna,则g'(a)=a-e/a
当0当a>e时,g'(a)>0,g(a)单增
所以,g(a)>g(e)=e-e=0
所以,alne-elna>0,即e^a>a^e
所以,f(a)>e^af(0)>a^ef(0)