求证:不论x、y、取何值是,x^2-4x+y^2-6y+13的值不小于0

问题描述:

求证:不论x、y、取何值是,x^2-4x+y^2-6y+13的值不小于0
RT

x^2-4x+y^2-6y+13 = x^2 - 4x + 4 + y^2 - 6y + 9
= (x - 2)^2 + (y - 3)^2 >= 0