f(x)=(x-1)^2+2,因为(x-1)^2≧0,①若a>1,则f(x)max=[(a+2)-1]^2+2=a^2+2a+3 f(x)min=(a-1)^2+2=a^2-2a+3,②若a≦1≦a+2,即-1≦a≦1,此时分2种情况考虑,1若1-a≦a+2-1,即a≧0时,(0≤a≤1）f(x)max=[(a+2)-1]^2+2=a^2+...