f(x)=-x^2+2x=-(x-1)^2+1f（x）的定义域和值域分别为［m，n］和［3m，3n］当n≤1时，f(x)在[m,n]上递增，那么f(m)=-m^2+2m=3m ==> m^2+m=0 f(n)=-n^2+2n=2n ==> n^2+n=0∵m当 m≤1当1 f(x)max=f(m)<1≠3n,不合题意；综上，m=-1,n=0
