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MathNet 2007-part-01 — 187 problems (EN–VI) Question 125

Math Olympiad Vault · MathNet 2007-part-01 — 187 problems (EN–VI)

Question 125

Let $n$ be an integer greater than $3$, and let $a_1, a_2, \dots, a_n$ be nonnegative real numbers with $a_1 + a_2 + \dots + a_n = 2$.

Determine the minimum value of
$$
\frac{a_1}{a_2^2+1} + \frac{a_2}{a_3^2+1} + \cdots + \frac{a_n}{a_1^2+1}.
$$