A relation is a set of ordered pairs. Yes, that means more than one ordered pair.

Domain: all the first coordinates in the ordered pairs.

Range: all the second coordinates in the ordered pairs.

Inverse: switch all the first and second coordinates.

For example, consider the relation {(2,5), (-3,8), (4,-4), (1,5)}.

The domain would be written D:{-3, 1, 2, 4}

The range would be written R:{-4, 5, 8}. Notice that the 5 is not written twice even though it appears twice. You only need to write numbers once.

The inverse would be written as; Inv:{(5,2), (8,-3),(-4,4), (5,1)}.

There are several ways to show relations. The easiest and most basic is just as a set of ordered pairs (like the example above). They can also be expressed in a table, a mapping, and a graph. When a relation is expressed as a graph, just write down the ordered pairs of the points and you just rewrote the relation as a set of ordered pairs. In a table the relation {(1,5), (4,-4), (3,8)} would look like this:

As a mapping, the same relation would look like this:

Whelp, that is about it. So, good luck. If you have any questions or comments let me know.

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