Školjka

%V0 Za $a,b,c>0$ dokaži da vrijedi: $$\left( \frac{2a}{b+c} \right)^{\frac{2}{3}}+\left( \frac{2b}{a+c} \right)^{\frac{2}{3}}+\left( \frac{2c}{a+b} \right)^{\frac{2}{3}} \geq 3 \text{.}$$