Patterns and Functions

1
Patterns and Functions

• Lesson 1.4

2
Writing a Function Rule

• Toothpicks example done in class

Relate The total number of toothpicks is one
more than 5 times the number of houses. Define
Let n the number of houses Let t the total
number of toothpicks. Write t 5n 1 This
is the function rule! So how many toothpicks
are needed to make 7 houses?
3
Example 2

• Laundry Time!
• Suppose you are washing and drying clothes at a
  self-service laundry. The relationship between
  the number of loads (input) and the cost (output)
  is a function. Use the table to write a function
  rule.

4

• Relate
• Define
• Write

5
Example 3

• Write a function rule for the relationship
  between the number of hours (input) and the
  number of miles (output) when you were traveling.

Function Rule
6
Independent Dependent Variables

• Looking at your text on page 28, read through
  Example 3 they give you. What do independent and
  dependent variables mean?
• Independent Variable
• Dependent Variable

7
Identify the independent and dependent variable
in the following situations

• The cooking time for an un-stuffed turkey is
  about 20 minutes per pound.
• The distance of the race determines how tired you
  are at the end of the day.
• Your skill playing the drums increases as the
  time you spend playing increases.
• The amount of people swimming in the billabong is
  usually about 20 more for every degree the
  temperature rises.

8
Domain and Range

• Maria earns 7 per hour for baby-sitting after
  school on Saturday. She works no more than 16
  hours a week.
• What are the independent and dependent variables?
• At what values would a chart or graph stop?
• Which is which?

9
You try

• Cody downloads songs onto his new ipod for .75
  each. He has between 3.00 and 6.00 to spend on
  songs.
• Independent and dependent variables?
• I amount of money he can spend
• D the of songs he can buy
• Domain and Range?
• Domain - 3 to 6
• Range 4 to 8 songs

10
Closing

• Group these terms into 2 related lists
• range, domain, dependent, independent, x-axis,
  y-axis, abscissa, ordinate
• Explain you choices.