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MathNet 2015-part-03 — 191 problems (EN–VI) Question 176

Math Olympiad Vault · MathNet 2015-part-03 — 191 problems (EN–VI)

Question 176

Prove that for all positive real numbers $a, b, c$ such that $a b c=1$ the following inequality holds:
$$
\frac{a}{2 b+c^{2}}+\frac{b}{2 c+a^{2}}+\frac{c}{2 a+b^{2}} \leqslant \frac{a^{2}+b^{2}+c^{2}}{3}
$$