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f(x^2-1998x)-f^2(2x-1999)>=1/4 (VI Soros Olympiad 1990-00 R1 9.4)

Source:

May 27, 2024
algebrafunctionalfunctional inequationinequalities

Problem Statement

Is there a function f(x)f(x), which satisfies both of the following conditions:
a) if xyx \ne y, then f(x)f(y)f(x)\ne f(y)
b) for all real xx, holds the inequality f(x21998x)f2(2x1999)14f(x^2-1998x)-f^2(2x-1999)\ge \frac14?