Example

Consider the relation defined by $\{ (0,1), (1,2), (2,3), (3,4), (4,5) \}$. What is the domain? What is the range? Can you think of a formula that describes the relation?

Solution

The domain is the set of all first coordinates:

The range is the set of all second coordinates:

In this example, each second coordinate is one more than the first coordinate:

where the 1st coordinates come from the set $\{0,1,2,3,4\}$. Another way to express the same formula is to say