Rectangular Coordinate System
One of the most valuable ways of representing a function is by graphical representation. By using graphs, we can obtain a “picture” of the function; by using this picture, we can learn a great deal about the function.
To make a graphical representation of a function, recall from Chapter 1 that numbers can be represented by points on a line. For a function, we have values of the independent variable as well as the corresponding values of the dependent variable. Therefore, it is necessary to use two different lines to represent the values from each of these sets of numbers. We do this by placing the lines perpendicular to each other.