Understanding Domain and Range Part 1
The domain of a function is the set of x-coordinates of the points in the function. The range of the function f is the set of y-coordinates of the points in the function. So if we have a function f with points (-3, -2), (-1, 3), (2, 3), and (5,4), then the domain of the function f is the set {-3, -1, 2, 5} and the range of f is the set {-2, 3, 4). Graphically, we can say that the domain is the “projection” of the points to the x-axis (see red points in the following figure).
The range of f is the projection of the points to the y-axis (see green points in the following figure). » Read more