`f(x,y) = tan(y/x)` Determine whether the function is homogenous and if it is, determine its degree

A function `f(x, y)` is called homogeneous if for some integer `n`

`f(tx, ty) = t^n f(x, y).`

The given function satisfies this condition with `n = 0:`

`f(tx, ty) = tan((tx)/(ty)) = tan(x/y) = f(x, y),`

and therefore it is homogeneous with the degree 0.

(although we have to note that for some x and y  `f(x, y)` is undefined)