My idea

来源: 于 2015-02-06 14:51:37 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

Try to break y^3+y into three terms in order to use A-G inequality for 6 terms

y^3+y >= (y^3+2y^2+y)/2

The original left >= 6*xy*(1/4)^{1/6}

6*(1/4)^{1/6}>9/2