Question 58
Find every $f : \mathbb{R} \to \mathbb{R}$ such that for any $x$ and $y$,
$$
f(x)^2 + 2y f(x) + f(y) = f(y + f(x)).
$$
$$
f(x)^2 + 2y f(x) + f(y) = f(y + f(x)).
$$
MathNet 2006 — Part 04 Question 58
Math Olympiad Vault · MathNet 2006 — Part 04