Relations and Functions

Kelley Wood

MEDT 7477

Dr. Cooper

Fall 2012

What is a Relation?

A RELATION in math is what you would

think of when you here the word relationship

referring to people.

It’s a correspondence between two things.

In Math:

A relation is listed as a set of

ordered pairs. We’re familiar with

x- and y-values in an ordered

pair, but we learned some new

vocabulary words that refer to

these by different names.

This is Dixi – She’s the X-value.

Her name is an acronym.

Domain

Input

X Value

Independent Variable

D.I.X.I

This is Roy D – He’s the y-

value.

His name is an acronym.

Range

Output

Y Value

Dependent Variable

R.O.Y. – D.

A Function is a Relation

In order for a relation to be a function, Dixi cannot

cheat on Roy-D.

There are various ways to represent relations. Listen as Ms. Grajkowske explains

the different ways.

Did you notice those relations were not

functions? Well they weren’t because -2 in the

domain was paired up with 2 and -2 in the range.That’s CHEATING!!!!

Remember in order for a relation to be a function,

each element in the domain can be paired with only one

element in the range.

To Recap: Different Ways to Represent Relations/Functions

Mapping Diagram

Ordered Pair

Table

Graph