Let R+ be the set of positive real numbers. Let f:R+→R+ be a function such that for all x,y∈R+ it holds that
yf2025(x)≥xf(y).
Show that there exists a positive integer n0 such that for all positive integers n≥n0 and for all x∈R+ it holds that
fn(x)≥x.
Remark. Here fn denotes the function f applied n times, this means fn(x)=n timesf(f(…f(x)…)).