Question 31
Does there exist a function $f : \mathbb{R} \to \mathbb{R}$ that satisfies for all real numbers $x, y$ the equation
$$
f(x) + f(f(y)) + f(f(f(x))) = x + y?
$$
$$
f(x) + f(f(y)) + f(f(f(x))) = x + y?
$$
MathNet 2024-part-02 — 168 problems (EN–VI) Question 31
Math Olympiad Vault · MathNet 2024-part-02 — 168 problems (EN–VI)