You will explore the concepts of relation, the domain (input) and range (output) of a relation using a real-life example involving songs and musicians. You will also learn how to represent a relation by listing ordered pairs, mapping, and graphing.
After completing this tutorial, you will be able to complete the following:
Relation terminology explained
A relation is actually a relationship between two sets. The first set is called the domain and is often referred to as the input. The second set is called the range and is often referred to as the output.
A relation happens when some elements in the domain (input) are paired with one or more elements from the range (output).
Relations are expressed in a variety of ways. A relation can be expressed in a mapping diagram (see the diagram below left). The domain (input) is on the left side and the range (output) is on the right side.
Relations can be expressed by graphing (see the diagram below middle). The ordered pairs created from either the mapping diagram or set of ordered pairs can be graphed as individual ordered pairs on a coordinate plane.
Finally, relations are also expressed by listing (see the diagram below right). The input value and output value can be written together to form an ordered pair. Each ordered pair represents one element in the relation.
Note that a relation can be expressed in all of these. They can also be quickly translated from one expression to the next.
The following key vocabulary terms will be used throughout this Activity Object:
· domain - the set of input values for which a relation is defined
· element - each object in a set; also called a member
· input - the elements that define the domain set
· mapping diagram - a visual representation of a relation such that some input values are paired with at least one output value
· ordered pairs - a pair of numbers used to locate a point on a coordinate plane. An ordered pair is written in the form (x, y) where x is the x-coordinate and y is the y-coordinate
· output - the elements that define the range set
· range - the set of all output values produced by a relation
· relation - a relationship between two sets of information where some value of the first variable is paired with one or more values of the second variable
· set - a group of entities with one or more common characteristics; entities can be referred to as members, elements, or objects
|Approximate Time||20 Minutes|
|Pre-requisite Concepts||Students should know the definitions of ordered pair, input, output, domain, and range.|
|Type of Tutorial||Concept Development|
|Key Vocabulary||domain, input, mapping|