1. Homework Answers

2. QUIZ TIME After you finish work on the warm up
Why did the skeleton visit a butcher shop?

3. Function Notation
Materials: handout (Why did the skeleton visit a butcher shop?), graph paper, quizzes

4. In this lesson you will Learn to use function notation
Use a graph to evaluate a function for various input values
Use an equation to evaluate a function for various input values

5. Definitions
Relation
A relationship between sets of information. Typically between inputs and outputs.
Function
A relation such that there is no more than one output for each input

6. 4 Examples of Functions X Y 10 2 15 -5 18 20 1 7 X Y -3 1 -1 4 5 7 3

7. 3 Examples of Non-FunctionsY 4 1 10 2 11 -3 5 3

8. Which do you prefer to write?
Function Notation
The f is the name of the function machine and the value inside the parentheses is the input. The expression to the right of the equal sign shows what the machine does to the input.
Which do you prefer to write?
Evaluate f when x = 25?
f(25) OR 5

9. Example If f(x) = 2x + 3, find f(5).
When evaluating, do not write f(x)!
You want x=5 since f(x) was changed to f(5)
You wanted to find f(5). So the complete final answer includes f(5) not f(x)

10. Substitute and Evaluate
Solving v. Evaluating
No equal sign
Equal sign
Substitute and Evaluate
The input (or x) is 3.
Solve for x
The output is -5.

11. EXAMPLE
You can use the function f(x)= x to approximate the wind chill temperature for a given actual temperature when the wind speed is 15 miles per hour. Both x and are in degrees Fahrenheit. Find f (x) for each given value of x. a. f(-10) b. f(0) c. x when f(x)=19 d. x when f(x)=-13
a) b) c) d)

12. Not all functions are expressed as equations.
Here is a graph of a function g. The equation is not given, but you can still use function notation to express the outputs for various inputs.
For example, g(0)=3, g(4)=6, and g(6)=1.
Can you find x-values for which g(x)=3?

13. Look at the graph below. What is the domain. What is the range
Look at the graph below. What is the domain? What is the range? Use the graph to find each function value in the table. Then do the indicated operations.
Domain: [0, 25] Range: [0, 20]

14. You try:

15. Homework: Packet p. 3 Tutorials: Mondays and Thursdays
Homework: Packet p. 3 Tutorials: Mondays and Thursdays. 1st half of lunch