I know from the chapter "functions" that $f(x)$ is a function of $x$ and to roughly put it, it maps $x$ values to another set called co-domain where all the $y$ values are.
But I also sometimes see $f(x,y)$ on internet. I can guess that it means some expression in $x$ and $y$.
I'm not familiar with them yet and they aren't in my high school syllabus but I'd love to know more about and I have a few questions,
What type of function is this? What's it called?
What does is represent? Can you also represent $f(x,y)$ using arrow diagram between $2$ sets?
Is $(x,y)$ in $f(x,y)$ an ordered pair? Or $f(x,y)$ is same as writing $f(y,x)$