Is the following inequality true for any a,b,c>0? I couldn't find a counterexample but I couldn't prove it either.
$\sum \sqrt{a+b} \ge \sqrt{2} \sum \sqrt{a}$
(The sum is cyclic)
Is the following inequality true for any a,b,c>0? I couldn't find a counterexample but I couldn't prove it either.
$\sum \sqrt{a+b} \ge \sqrt{2} \sum \sqrt{a}$
(The sum is cyclic)
$$\sqrt{a+b} \ge \frac{\sqrt{2}}{2} (\sqrt{a}+\sqrt{b}) $$ $$a+b \ge \frac{a+2\sqrt{ab}+b}{2}$$ $$a-2\sqrt{ab}+b \ge 0$$ $$(\sqrt{a}-\sqrt{b})^2 \ge 0$$ which is obviously true
Summing the inequality cyclically gets us to the desired inequality with equality for a=b=c