f(x)=x^2
=[(x-1)+1]^2 (x>1,增函数)
f(x)=x^2-4x+4
=(x-2)^2
=[(x-1)-1]^2
=[1-(x-1)]^2 (xf(m^2-2)
（1）2m+14
m-12
m3
且m^2-2