已知x,y为实数,且x⒉＋1／2y⒉＋4≤xy+2y,求x,y的值?_数学解答

已知x,y为实数,且x⒉＋1／2y⒉＋4≤xy+2y,求x,y的值?

人气：497 ℃　时间：2020-05-23 17:58:21

解答

x^2+1／2y⒉+4≤xy+2y
x^2+1／2y^2+4-xy-2y<=0
(x-y/2)^2+y^2/4-2y+4<=0
(x-y/2)^2+(y/2-2)^2<=0
x-y/2=0, y/2-2=0
y=4, x=2.