1.9.12 functions/relations

Bell WorkJan. 9, 2012

1. How many solutions are there for ?

2. Fill in the green boxes in the following table:

Write the answers in your composition book, labeling the top of the page with the date.

RelationBrainstorm

A relation is a set of related information

Example:A list of names of people in our class and their heights

Name Height

A relation could also look like this:

A relation could also look like this:

Because the relation has we can graph it

two types of information, on a coordinate plane.

If all relations that exist were represented by this pentagon...

RELATIONS

If all relations that exist were represented by this pentagon...

...then this circle represents all the possible functions. Every function is a relation.

RELATIONS

FUNCTIONS

Functions are "well-behaved" relations. To be a function, a relation has to follow one rule:

Each x-value must relate to 1 and only 1 y-value.

x y

1 2

2 3

3 3

4 5

FUNCTION

x y

1 2

2 3

2 4

4 5

NOT A FUNCTION

Quick Poll:Is this relation a

function?

Quick Poll:Is this relation a

function?

In dating relationships, what is one thing that someone could do that would lead most people to break up immediately?

FunctionalRelationships

Picture a world where in dating relationships, guys can only date one girl, but girls can date as many guys as they want.

A Function is like this. ·Guys are x-values·Girls are y-values·Domain: all x-values, or guys, in a relation·Range: all y-values, or girls, in a relation

As a class, we are going to create a set of functional relationships according to this rule.

FunctionalRelationships