1. Do Now:
Determine if the following relations are functions. For part (b) only, state the domain and the range.
NOT A FUNC-TION
{(-2,5), (1.25,8), (1,4), (11,0), (1,6)} 4 9 17 -6 4 8
NOT A FUNCTION

2. Aim: What notation do we use for functions?
Homework: Red Book
Pg 504: 7-21 odd, 29

3. Remember: A relation is any set of ordered points
In mathematics, we use equations to talk about many ordered points at once.
=>So, all equations are relations
=>Many equations are functions
(and these are the ones that we focus on)

4. Examples:
These are not functions:
These are functions:

5. To show that equations are functions…
We change y to f(x)
Pronounced
“f of x”

6. Benefits:
Clearly shows how to find the output (the corresponding element of the range
Clearly shows your input (an element of the domain)

7. Using Function Notation
Two of the elements in the domain of f(x) = x+5 are 1 and 4. Find the corresponding range elements.
f(x)= x+5
f(1)= (1)+5= 6
So 1 is related to 6
f(4)= (4)+5 = 9
So 4 is related to 9

8. Sample Test Question:
If ,
Then find f(x+1).

9. (If you included these values, this would not be a function!)
Sample Test Question:
What this is really asking:
-Find the values of x that will NOT relate to an element of the range, and don’t include them in the domain.
(If you included these values, this would not be a function!)