Problem
ALG-B3-M09-P005 Order and Involution
#5
★★☆☆☆ Level 2 of 5
Let \(f\) be strictly increasing and \(f(f(x))=x\). Prove that \(f(x)=x\).
Compare \(x\), \(f(x)\), \(f(f(x))\).
If \(f(a)>a\), then \(f(f(a))>f(a)\), so \(a>f(a)\), contradiction. If \(f(a)
Iteration task inside the inequality module.