Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2005 — Part 03 Question 105

Math Olympiad Vault · MathNet 2005 — Part 03

Question 105

Find all functions $f : (0; +\infty) \to \mathbf{R}$ such that the equality
$$
f(x)f(y) = f(xy) + 2005 \left( \frac{1}{x} + \frac{1}{y} + 2004 \right)
$$
holds for all positive real $x$ and $y$.