ta có: \(x\sqrt{x}+y\sqrt{y}\ge x\sqrt{y}+y\sqrt{x}\) (1)
\(\Leftrightarrow\left(\sqrt{x}+\sqrt{y}\right)\left(x-\sqrt{xy}+y\right)\ge\sqrt{xy}\left(\sqrt{x}+\sqrt{y}\right)\)
\(\Leftrightarrow\left(\sqrt{x}+\sqrt{y}\right)\left(x-\sqrt{xy}+y-\sqrt{xy}\right)\ge0\)
\(\Leftrightarrow\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{x}-\sqrt{y}\right)^2\ge0\) luôn đúng
=> (1) luôn đúng => đpcm
ko bít ????????????????????????????______________________________________????????????????????????????????????????