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MathNet 2017-part-01 — 176 problems (EN–VI) Question 40

Math Olympiad Vault · MathNet 2017-part-01 — 176 problems (EN–VI)

Question 40

Let $a$, $b$, $c$ be positive real numbers such that $abc = 1$. Prove that
$$
\frac{1}{a^5+b^5+c^2} + \frac{1}{b^5+c^5+a^2} + \frac{1}{c^5+a^5+b^2} \le 1
$$