MathDB
Problem 1

Source: 2011 Armenian Republican Olympiad

August 1, 2016
functionalgebra

Problem Statement

Does there exist a function f ⁣:RRf\colon \mathbb{R}\to\mathbb{R} such that for any x>y,x>y, it satisfies f(x)f(y)>xy.f(x)-f(y)>\sqrt{x-y}.