Let's say we have the equation: $$x^y=y^x$$ what are the solutions when $x,y \in \Bbb Z$ for ${x}\ne{y}$..
The only one I have found is 2 and 4. There are infinite non-integer solutions but I am interested in the integer ones. Also you can find a new definition for $e$ from this equation $e=x^{\frac{y}{xln(y)}}$ and also $log_x(y)=\frac{y}{x}$