| x_1x_4-x_1x_5 +x_2x_5 -x_2x_6+x_3x_6-x_3x_4| >= 4M^2
Source: Czech And Slovak Mathematical Olympiad, Round III, Category A 1982 p2
September 10, 2024
algebrainequalities
Problem Statement
Given real numbers , , , , , . Let denote the maximum of their absolute values. Prove that it is valid