Question 158
Find all function $f: \mathbb{R}^+ \to \mathbb{R}^+$ such that for $x, y, z \gt 0$ pairwise distinct then
$$
f(x)^2 - f(y)f(z) \le f(xy)f(y)f(z)[f(yz) - f(zx)].
$$
$$
f(x)^2 - f(y)f(z) \le f(xy)f(y)f(z)[f(yz) - f(zx)].
$$
MathNet 2023-part-05 — 191 problems (EN–VI) Question 158
Math Olympiad Vault · MathNet 2023-part-05 — 191 problems (EN–VI)