2019 All Russian MO Grade 11 P2
Source:
May 1, 2019
algebratrigonometry
Problem Statement
Is it true, that for all pairs of non-negative integers and , the system
\begin{align*}
\tan{13x} \tan{ay} =& 1 \\
\tan{21x} \tan{by}= & 1
\end{align*}
has at least one solution?