1. Do Now: Solve the following:
g(x) = 2x2 – f(x) = 4x – h(x) = 3 – 5x

2. We’ve been working with functions but what are they??
What is a Function??
We’ve been working with functions but what are they??

3. First….Relations
A relation is information that can be represented by a set of ordered pairs
(Room 615, Ms. Taylor’s Math Class)
(Room 617, Mrs. Sawyer’s Math Class)
(Room 628, Mr. Green’s Math Class)

4. Remember… A relation can have forms other than a coordinate pair:
Mapping
Table
Graph

5. Functions
A function is a relation in which each input (domain/x-value) is paired with exactly one output (range/y-value)

6. Think of your output number as a mailbox.
A function is a relation in which each input (range/y-value)
is paired with exactly one output (domain/x-value)
To help remember & understand the definition:
Think of your input number as a letter.
Think of your output number as a mailbox.

7. A function is a relation in which each input (range/y-value)
is paired with exactly one output (domain/x-value)
Input number
Output number
Can you have one letter going to two different mail boxes?
Not a FUNCTION

8. A function is a relation in which each input (range/y-value)
is paired with exactly one output (domain/x-value)
Input number
Output number
Can you have two different letters going to one mail box?

9. So Basically…
If there is more than one of the same numbers in the domain….not a function!!
CONNOT REPEAT THE X-VALUE
However, we can have more than one of the same y-value

10. Is this a function? x y
Yes, it is a Function 1 2 3 4
x y 5 6 7 5 6 7

11. Is this a Function?
Not a Function x y
x y 5 6
1 7
1 6 1 2 5 6 7

12. Is this a Function?
Not a function x y 5 6 8 11 1 2 3
x y 5 6 11 8

17. Class Work Worksheet The answers are posted on the board!
When done get out your Math Weekly #6 and work on it.
If you finished it, have Ms. Taylor check it and help others…DO NOT LET THEM COPY, I WILL RIP YOUS AND THEIRS UP!