Functions What is a What are they function

Functions What is a What are they? function? thea How What do I tell are whether relation is a function? different ways to represent a

Relation – pair of coordinates for input Functions and output. Usually a What is a coordinate pair (x, y) function? Domain – theare x the What coordinate different Rangeways – the yto coordinate represent a

Ex: y=3 x+1 Functions Domain: what x values What is a are allowed? function? Range: what are the y What the values that come out of different the equation? ways to represent a

A Mapping Diagram is one way to show a relation: Ex: (1, 4) (-2, -5) (0, 1) (-1, -2) In a mapping diagram, the domain (x) values are listed in the left circle and the range (y) values are listed in the right circle. Then, draw a line from each domain value to its corresponding y value.

Functions are relations for which there is exactly one domain (x) value for every range (y) value. In a list of ordered pairs, a relation is a function only if the x values are not duplicated.

In a mapping document, a relation is a function if there is only one line coming from each domain (x) value Domain Range -2 0 3 4 6 4 5 1 This relation IS a function. Domain -2 0 3 4 Range 6 4 5 1 This relation IS NOT a function.

What if you only have a picture of a relation? Use the vertical line test: if you can draw a vertical line through the relation and hit more than one point, then the relation is NOT a function. Y ! s e Is the relation on the left a function?

Examples of Functions

Non Examples of Functions