When the domain and the codomain are sets of real numbers, each such pair may be thought of as the Cartesian coordinates of a point in the plane; the set of these points is called the graph of the function.
Rikala domain lan kodomain inggih punika himpunan wilangan real, soang-soang punika polih kaanggapin pinaka koordinat cartesian ring abuah titik ring pesawat.