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Bosnia and Herzegovina TST 2012 Problem 2

Source:

May 19, 2012
trigonometryinequalitiesinequalities proposed

Problem Statement

Prove for all positive real numbers a,b,ca,b,c, such that a2+b2+c2=1a^2+b^2+c^2=1:
a3b2+c+b3c2+a+c3a2+b31+3.\frac{a^3}{b^2+c}+\frac{b^3}{c^2+a}+\frac{c^3}{a^2+b}\ge \frac{\sqrt{3}}{1+\sqrt{3}}.