比较大小,说明理由：①（x+y)/2 ②根号下xy ③2xy/(x+y)
问题描述：
比较大小,说明理由：①（x+y)/2 ②根号下xy ③2xy/(x+y)
答
（√x+（√y）^2 = x+y-2（√xy)>=0
(x+y)/2>=（√xy)
2/(x+y)2xy/(x+y)即(x+y)/2>=（√xy)>=2xy/(x+y)