Is it possible to find two functions $f,g:\mathbb R\longrightarrow \mathbb R$ and a rational function $S(u,w)$ in two variables such that \[\cos(xy)=S(f(x),g(y))\] for all real numbers $x,y$. (Recall that a rational function in 2 variables is a quotient of two polynomial functions in two variables). The problem was solved by Josiah Moltz and Dr Mathew Wolak. Their solutions follow the same idea as our in-house solution. For details see the following link {{:pow:2025sproblem2.pdf|Solution}}.