MathDB
Romania District Olympiad 2001 - Grade IX

Source:

March 12, 2011
number theory proposednumber theory

Problem Statement

Conside a positive odd integer kk and let n1<n2<…<nkn_1<n_2<\ldots<n_k be kk positive odd integers. Prove that:
n12−n22+n32−n42+…+nk2≥2k2−1n_1^2-n_2^2+n_3^2-n_4^2+\ldots+n_k^2\ge 2k^2-1
Titu Andreescu
Back to ProblemsView on AoPS