GRAPHING A FUNCTION RULE

Continuous or Discrete• Length of hair over a month• Number of cars in the parking lot

over a 24 hour period• Student enrollment at Strack over

2 years• Rainfall totals each month for the

summer• Number of desks in a classroom

over the year• Time you walk your dog each day

for a week

EXAMPLE 1 You are paying to print pictures from

your digital camera at the photo shop. You choose 4 x 6 pictures for all of them. These prints cost $0.49 each.

Write a function rule for this. Make a table. Now graph it.

Continuous or discrete?

Dependent variable (y)Independent variable (x)

Scale

GRAPH THE FUNCTION RULE: Y = 3X - 2

Continuous or discrete?

Dependent variable (y)Independent variable (x)

Scale

x y

Example 2

EXAMPLE 3 The cost C, in dollars for a health club

membership depends on the number m of whole months you join. This situation is represented by the function rule C = 49 + 20m.

What does the 49 represent? What does the 20 represent Continuous or discrete? Independent variable? Scale? Graph:

EXAMPLE 4 Graph: y = |x| + 2

EXAMPLE 5 Graph: y = x2 + 4

EXAMPLE 6 The area, A, of a rectangle is a function

of its width, w. If the length is always 5 cm in this case, write a function rule for this situation.

Continuous or discrete? Independent variable? Dependent variable? Scale?

EXAMPLE 7 What shape would the graph of y = x3

be? How can you find out? What about y = x4? What about y = x5? Do you see a pattern?