设g(x)=-1/4x+5/4,则问题等价于x1,x2∈[1,1-m],f(x)max<g(x)min
由(1)知,当m∈(-1,0)时,f(x)在[1,1-m]上单调递增,f(x)_max=f(1-m)=(2-m)/e^(1-m) ,
g(x)在[1,1-m]上单调递减,g(x)_min=g(1-m)=1/4 m+1,
即证(2-m)/e^(1-m) <1/4 m+1,化简得4(2-m)<e1-m[5-(1-m)]
令1-m=t,t∈(1,2)
设h(t)=et(5-t)-4(t+1),t∈(1,2),
h'(t)=et(4-t)-4>2et-4>0,故h(t)在(1,2)上单调递增.
∴h(t)>h(1)=4e-8>0,即4(2-m)<e1-m[5-(1-m)]
故(2-m)/e^(1-m) <1/4 m+1,得证.