Functions Introduction

1. Aim: What is a function?
Do Now: Place your contracts in the basket. Take
out a pen or pencil and a sheet of paper.
You have 50 minutes to complete the diagnostic.
This counts for Quiz 1. You will not be graded on correctness.
Your grade will depend on how many questions you answer
and how much work you show.

2. Functions as a set of ordered pairs.
Domain: The set of all inputs in a function, or the set of x values.
Range: The set of all outputs of a function, or the set of y values.
DEFINITIONS:

3. A function is a relation in which each
element of the domain is paired with
exactly one element in the range.
Example: {(1, 1), (2, 4), (3, 9), (4, 16)}
Domain Range
Mapping Diagram

4. Ordered pairs on the grid
.
.
.
.
Write the ordered pairs for the relation
shown in the graph.
What is the Domain? (x values)
What is the Range? (y values)
Is this relation a function?
Domain Range

5. Is the relation {(1, 3), (4, 3), (-2, -4),(0, -5)}
a function or not? Why or why not?
Domain Range . .
. .

6. Function or not a function?
{(0, 1), (2, 2), (0, 3), (4, 5)}
Domain Range
Not a function because the same value in the domain is
paired with two different values in the range.

7. Visually, a relation is a function if it passes
the vertical line test.
When a vertical line is drawn if it only hits the graph of
a relation once, then the relation is a function.
✔ ✖

8. Are these graphs of functions?