Question 72
Find all (not necessarily strictly) monotonic functions $f: \mathbb{R} \to \mathbb{R}$ with
$$
f(x+y)^3 = f(x^3) + f(y^3) \text{ for all } x, y \in \mathbb{R}.
$$
$$
f(x+y)^3 = f(x^3) + f(y^3) \text{ for all } x, y \in \mathbb{R}.
$$
MathNet 2023-part-01 — 191 problems (EN–VI) Question 72
Math Olympiad Vault · MathNet 2023-part-01 — 191 problems (EN–VI)