解；f(x)=x^2-2(2a-1)x+5a^2-4a+2
=(x-2a+1)^2-4a^2+4a-1+5a^2-4a+2
=(x-2a+1)^2+a^2+1
若2a-1>=1时a>=1则f(x)min=f(1)=(2-2a)^2+a^2+1
=5a^2-8a+5
若0=