Question 80
Find all functions $f : \mathbb{R} \to \mathbb{R}$ with the property
$$
|f(x+y) - f(x-y) - 2y| \le y^2, \quad \forall x, y \in \mathbb{R}.
$$
$$
|f(x+y) - f(x-y) - 2y| \le y^2, \quad \forall x, y \in \mathbb{R}.
$$
MathNet 2016-part-04 — 184 problems (EN–VI) Question 80
Math Olympiad Vault · MathNet 2016-part-04 — 184 problems (EN–VI)