This is supposed to be one of the easiest problems from BdMO 2014. But I can't seem to find a rigorous way of solving this problem. Am I missing something?
\(x\), \(a\), \(b\) are positive numbers such that if \(a>b\), \(f(a)>f(b)\) and \(f(f(x))=x^2+2\). What is the value of \(f(3)\)?
This also happens to be my first note!