1. SWBAT… graph piecewise functions
Wed, 9/28
SWBAT… graph piecewise functions
Agenda
Warm Up (10 min)
Quiz (20 min)
Graphing (15 min)
Warm-Up:
1.) Turn in HW#7 in the blue folder
2.) Review your graphing linear equations using a table of values and absolute value notes including transformations
Review PPT3: Piecewise functions

2. 2.) On one graph paper square: 1. Graph x = 3 2. Graph y = -2
1.) Cut a piece of graph paper into 4 squares
2.) On one graph paper square:
1. Graph x = 3
2. Graph y = -2
3.) On another graph paper square, graph y = x + 1
Review PPT 3: Piecewise functions

3. SWBAT… graph piecewise functions
Wed, 9/28
SWBAT… graph piecewise functions
Agenda
Warm Up (10 min)
Piecewise functions (35 min)
Warm-Up:
1.) Cut a piece of graph paper into 6 squares
2.) On one graph paper square:
1. Graph x = 3
2. Graph y = -2
3.) On another graph paper square, graph y = x + 1
HW#5: Piecewise functions

4. Graphing Horizontal & Vertical Linesy x
When you are asked to graph a line, and there is only ONE variable in the equation, the line will either be vertical or horizontal. For example …
Graph x = 3
y = –2
Since there are no y–values in this equation, x is always 3 and y can be any other real number.
Graph y = –2
Since there are no x–values in this equation, y is always –2 and x can be any other real number.
x = 3

5. SWBAT… graph piecewise functions
Thurs, 9/29
SWBAT… graph piecewise functions
Agenda
Warm Up (10 min)
Piecewise functions (35 min)
Warm-Up:
1.) On one graph paper square:
1. Graph x = -5
2. Graph y = 1
2.) On another graph paper square, graph y = x + 1
3.) On a number line graph x > 3
HW#5: Piecewise functions

6. Graph x = -5 Graph y = 1 y = 1 x = -5
Since there are no y–values in this equation, x is always -5 and y can be any other real number.
y = 1
Graph y = 1
Since there are no x–values in this equation, y is always 1 and x can be any other real number.
x = -5

7. Graph y = x + 1 Step 1: Solve for y
Step 2: Look at the y-intercept (b) and plot where the graph crosses the y-axis.
y = x + 1 y
Step 3: Use the slope (rise/run) to determine the next point and plot.
Slope = 1 = 1/1 x
Step 4: Draw a line through both points. Be sure to extend the line and put arrows at both ends. (Use a ruler!)
Step 5: Label your line

8. Endpoints when graphing
<
> ≤ ≥

9. Endpoints when graphing
<
> ≤ ≥
Open Circle
Closed circle

10. Piecewise Function Graph f(x) =
A piecewise function is any function that is in, well, pieces!
Piecewise functions indicate intervals for each part of the function
Graph f(x) =

11. Step 1: Graph f(x) = 1 f(x) = 1 Step 2 :
Erase part of the graph where x >3
Step 3:
Graph f(x) = x + 1
Step 4:
Erase part of the graph where x<3 y
f(x) =
f(x) = 1 x

12. Erase part of the graph where x >3
Step 1:
Graph f(x) = 1
Step 2 :
Erase part of the graph where x >3
Step 3:
Graph f(x) = x + 1
Step 4:
Erase part of the graph where x<3 y
f(x) =
f(x) = {1 x < 3 x 3

13. f(x) = x + 1 Step 3: Graph f(x) = x + 1 Step 1: Graph f(x) = 1
Erase part of the graph where x >3
Step 3:
Graph f(x) = x + 1
Step 4:
Erase part of the graph where x<3 y
f(x) = x + 1
f(x) = x

14. Erase part of the graph where x<3
Step 1:
Graph f(x) = 1
Step 2 :
Erase part of the graph where x >3
Step 3:
Graph f(x) = x + 1
Step 4:
Erase part of the graph where x<3 y
f(x) =
f(x) = {x+1 x > 3 x 3

15. Summary of steps for our example
f(x) =
Step 1:
Graph f(x) = 1
Step 2 :
Erase part of the graph where x >3
Step 3:
Graph f(x) = x + 1
Step 4:
Erase part of the graph where x<3

16. More Examples
Go to the following website for more examples on graphing piecewise functions:

17. The graph shows the monthly fee for Cell Zone
The graph shows the monthly fee for Cell Zone. Use it to answer the following questions: 1) What is the monthly fee? 2) How many minutes are included in the monthly fee? 3) If a customer goes over the minutes included in the fee, how much will they be charged per minute ($/min)? 4) Write a function for this plan.
$40
400 minutes
(60 – 40) / (600 – 400) = $0.10/min. This is slope (rate of change), meaning for every minute I talk (after 400 minutes), I will be charged $0.10.
f = Fee
m = Total minutes
f(m) = m ≤ 400
(m-400) m > 400 17