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\sqrt{(1-a^2)(1-b^2)} > \frac{a}{2b}+\frac{b}{2a}-ab-\frac{1}{8ab}

Source: Czech And Slovak Mathematical Olympiad, Round III, Category A 1994 p6

February 20, 2020
inequalitiesalgebra

Problem Statement

Show that from any four distinct numbers lying in the interval (0,1)(0,1) one can choose two distinct numbers aa and bb such that (1a2)(1b2)>a2b+b2aab18ab\sqrt{(1-a^2)(1-b^2)} > \frac{a}{2b}+\frac{b}{2a}-ab-\frac{1}{8ab}