Question 88
Find all pairs of real numbers $(x, y)$ that satisfy
$$
\begin{cases} x + \sin x = y, \\ y + \sin y = x. \end{cases}
$$
$$
\begin{cases} x + \sin x = y, \\ y + \sin y = x. \end{cases}
$$
MathNet 2013 Question 88
Math Olympiad Vault · MathNet 2013