Cho $a,b,c>0$ chứng minh
$\frac{3a}{\sqrt{2}(b+c)+(3-2\sqrt{2})\sqrt{bc}}+\frac{3b}{\sqrt{2}(c+a)+(3-2\sqrt{2})\sqrt{ca}}+\frac{3c}{\sqrt{2}(a+b)+(3-2\sqrt{2})\sqrt{ab}}\geqslant \sqrt{1+\frac{8(a^{2}+b^{2}+c^{2})}{ab+bc+ca}}$
Edited by Ngoc Hung, 01-05-2016 - 06:04.
