IMO Shortlist 2004 problem A1


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Dodao/la: arhiva
2. travnja 2012.
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Let n \geq 3 be an integer. Let t_1, t_2, ..., t_n be positive real numbers such that

n^2 + 1 > \left( t_1 + t_2 + ... + t_n \right) \left( \frac{1}{t_1} + \frac{1}{t_2} + ... + \frac{1}{t_n} \right).

Show that t_i, t_j, t_k are side lengths of a triangle for all i, j, k with 1 \leq i < j < k \leq n.
Izvor: Međunarodna matematička olimpijada, shortlist 2004