MathDB

Nice functional equation

Source: Iran '99, Bosnian TST 2008, 2.nd day

May 24, 2006

Problem Statement

Find all functions

f: \mathbb{R}\rightarrow \mathbb{R}

satisfying f(f(x) \plus{} y) \equal{} f(x^2 \minus{} y) \plus{} 4f(x)y for all

x,y \in \mathbb{R}