Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2026 — Part 06 Question 138

Math Olympiad Vault · MathNet 2026 — Part 06

Question 138

A function $f : \mathbb{Q}_+ \to \mathbb{Q}_+$, where $\mathbb{Q}_+$ denotes the (strictly) positive rational numbers, satisfies
$$
f(f(x) + f(y)) = \frac{xy}{x+y}
$$
for any $x, y \in \mathbb{Q}_+$. Given $f(1) = 2023$, find $f(2023)$.