## 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