A Periodic But Not Fixed PointGeometry Level 5
For every integer \(k\) we define a function \(f_k \) by the formula \[f_k(x)=100x-k\sin( x)\]
What is the smallest positive integer value of \(k,\) such that for some real \(\alpha\), we have \(f_k(f_k(\alpha))=\alpha,\) but \(f_k(\alpha )\neq \alpha\)?
Details and assumptions
The function is evaluated in radians. There is no degree symbol in the problem.