Function's graph

Let  f  be   a function with a domain  A and Oxy a coordinate system. The set of points M(x, y) to which it applies  y  =  f(x), ie the set of points M(x, f(x)),  x ∈A, it is said the graph  of f and symbolized usually with C f. The equation, then,  y  =  f( x) is verified only by its points C f. Therefore, the y =  f(x) is the equation of its graph  f. Because each  x ∈A  is assigned to only one y∈R, there are no points in  its representation line of  f  with the same abscissa. This means that every vertical line has with its graphical representation  of f  at most a common point.
In mathematics, the abscissa and the ordinate are respectively the first and second coordinate of a point in a coordinate system.