Name: Jeremy Gibbs

Date: December 12, 1997

Grade: Ninth

Class: Algebra I

Topic: linear functions with graphing calculators

Behavioral Objective: Students will be able to complete a worksheet with 80% accuracy.

They will use their technological skills with the calculators along

with their inductive skills to be able to determine how a and b affect

the equation.

Anticipatory Set and Purpose: Correct Response:

There will be two warm-up problems on the board when the

students arrive to begin working. They are both linear equations

to be done by hand, y = 5x + 2 and y = (1/2)x - 3. This lesson

will have been completed the previous day.

  1. What kind of functions have we been working with? Linear, or ax + b, or

any variation.

  1. How did we plot these graphs? Put in numbers for x

and y, plot by hand.

  1. How many points did we need to plot them? 3
  1. Now, let’s look at your warm-up problems. Did everyone get

the first graph? (Have someone draw it on the board.)

  1. How about the second one? (Have another person draw it on

the board.)

5 minutes

Instructional Input:
  1. Now, let’s define some terms of the functions. First of all,

does anybody know what the point is called where it

crosses the y axis? The y-intercept

  1. What do we call the angle of the lines? The slope
  1. Luckily for us, there is an easier way to plot these graphs.

This will be very helpful when we have more complicated

functions. We will use a graphing calculator.

  1. I am passing out the calculators to you now. They are very

expensive, so be very careful with them.

  1. I am also passing out a worksheet that we will work on during

class.

  1. First of all, let’s look at the calculator. Turn on by pressing the

"on" key in the bottom left. Go to "Y =" to get where we will

plot the graphs. Let’s first put in y = x. Hit the "X-Variable key,

then plot it by pressing graph.

  1. Did everyone get that? Yes
  1. Find the y-intercept by looking to see where the function crosses

the y-axis. If you can’t see it very well, then use the trace function

using the "Trace" key found at the top of your calculator. Then, you

can use the "Zoom" key and Zoom-in function to get a better estimate.

  1. What did you get for the y-intercept of this first problem? Zero
  1. Now, find the slope. We can use the "Trace" key again. We will use

the slope formula that we learned last week, (y2 - y1)/(x2 - x1). Our

points will be found simply by pushing to the right on the right arrow

on the right side of the calculator to get x2 and y2. Then, push back to

the left to get x1 and y1. Put them in the formula. What did you get? one

  1. Now, I will give you the next ten minutes to work out the first

three. If you need any help, I will be available.

  1. Now that we have worked out the first three, what happens to

the function as b is increased? Decreased? The function

moves up,

down.

  1. What happens when a is increased? The function

becomes more

vertical.

  1. Why is this? What does this mean? The slope

increases.

20 - 25 minutes

 

 

Checking for Understanding:
  1. Take five minutes to write in your journals. Write what you

learned from this lesson, what you liked about it, and what you

didn’t like about it. Also, work on problem number 4 to put in

your journal. I will be around to check after the five minutes to

see if you need any help.

  1. All right, finish the thought you are on in the journal and I will

come around to look at them.

  1. Did anybody have any questions about the calculators and how

to use them?

10 minutes

Conclusion:
  1. Your assignment will be to complete the worksheet

that I gave you. You have plenty of time to work on

it now so that you can get it done and not have to

take it home.

1 minute

Materials:

graphing calculators (for all of the students and for the teacher)

overhead screen (to teach to the whole class)

worksheet