Với $x,\,y$ dương thì:
$$\frac{1}{x}+ \frac{1}{x+ 2\,y}+ \frac{1}{2\,x+ y}\geqq \frac{25}{3\left ( 4\,x+ y \right )}$$
Spoiler
Với $x,\,y$ dương thì:
$$\frac{1}{x}+ \frac{1}{x+ 2\,y}+ \frac{1}{2\,x+ y}\geqq \frac{25}{3\left ( 4\,x+ y \right )}$$
$\frac{1}{3x}+\frac{1}{3x}+\frac{1}{3x}+\frac{1}{x+2y}+\frac{1}{2x+y} \geq \frac{5}{\sqrt[5]{3x.3x.3x.(x+2y)(2x+y)}} \geq \frac{25}{3x+3x+3x+x+2y+2x+y}=\frac{25}{3(4x+y)}$ (???)
"WHEN YOU HAVE ELIMINATED THE IMPOSSIBLE, WHATEVER REMAINS, HOWEVER IMPROBABLE, MUST BE THE TRUTH"
-SHERLOCK HOLMES-
0 thành viên, 2 khách, 0 thành viên ẩn danh