Question 152
Find all functions $f: \mathbb{Q}^+ \to \mathbb{Q}^+$ such that
$$
f(x^2 f(y)^2) = f(x)^2 f(y)
$$
holds for all positive rational numbers $x$ and $y$.
$$
f(x^2 f(y)^2) = f(x)^2 f(y)
$$
holds for all positive rational numbers $x$ and $y$.