Question 95
Find all functions $f : \mathbb{R}^+ \to \mathbb{R}^+$ such that
$$
f(x + f(x) + f(y)) = 2f(x) + y
$$
holds for all $x, y \in \mathbb{R}^+$.
$$
f(x + f(x) + f(y)) = 2f(x) + y
$$
holds for all $x, y \in \mathbb{R}^+$.
MathNet 2021 — Part 01 Question 95
Math Olympiad Vault · MathNet 2021 — Part 01