MathDB
f(x + f(y)) + f(x - f(y)) = x

Source: Canada Repêchage 2016/4

June 19, 2016
algebrafunctional equationfunction

Problem Statement

Determine all functions f:RRf: \mathbb{R} \rightarrow \mathbb{R} such that f(x+f(y))+f(xf(y))=x.f(x + f(y)) + f(x - f(y)) = x.