IMO Shortlist 1967 problem 6
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arhiva2. travnja 2012. Prove the following inequality:
where
%V0
Prove the following inequality:
$$\prod^k_{i=1} x_i \cdot \sum^k_{i=1} x^{n-1}_i \leq \sum^k_{i=1} x^{n+k-1}_i,$$ where $x_i > 0,$ $k \in \mathbb{N}, n \in \mathbb{N}.$
Izvor: Međunarodna matematička olimpijada, shortlist 1967