So the other day, at the end of 'little lunch', I was walking to the Maths staffroom with a cup of coffee in my hand, ready to get into much-needed marking, when all of a sudden one of my colleagues comes towards me with a smile from ear to ear. I asked him, 'what's happened ... did the Wallabies win a test match' He said, 'No, I just did trig graphs with my Year 11's ... on the graphics calculator. I hooked up the calculator to the data projector (with some teething difficulties) and dived straight into it'. I replied 'that's great, how did it go' and he said 'it was excellent, I was able to show them so much'. What makes this story particularly sweet is that this teacher is 64 years old.

Lesson 7
This lesson is going to graph a couple of a straight lines, using a single function to generate others. The main learning I see in this lesson is the settings on the calculator and how we enter subsequent functions.

Part 1 - Setting up the calculator
Turn your calculator on and jump straight into GRAPH mode (figure 1). We are going to make sure some settings are the way we want them. Enter the SETUP menu, which can be accessed by pressing SHIFT MENU. Make sure the settings are like in figure 2 and 3. A description of the settings is given below:

• AXES - simply the setting that shows or hides the x and y axes.
• GRID - this setting places dots on the number plane at integer values.
• LABEL - places the x and y on the axes (sometimes in the wrong positions - better left off)

Press EXIT to leave the SETUP menu and enter the ViewWindow by pressing SHIFT F3. We are going to use the initial settings for the window which can be set by pressing INIT (F1) (figure 4).

Let's enter in two functions. In Y1, we'll use the equation y = x - 1. The only part we enter is the x - 1. Remember to use the button below the red ALPHA key for the variable x. The result should look like figure 5.

In Y2, we are going to see what happens to the graph when we add 2 to the function. The syntax will look like this Y2 = Y1 + 2. The only part we enter is the Y1 + 2. If you are like me, you think the Y is simply a matter of pressing ALPHA Y, but unfortunately this is not the case. To access the variable Y, you need to press VARS (stands for Variables and it is just left of the MENU key). The next keysteps are:

VARS GRPH (F4) Y (F1)

The end result should look like figure 6 but in blue.

The last part of this is to take advantage of the colour screen on this calculator. Press EXIT repeatedly until you are at the initial menu in GRAPH mode. Move the bar with your up and down arrow keys so it is on Y2. You will see the option COLR (F4). Enter this menu then select Orng (F2) (figure 6).

Part 2 - Graph the functions
All the hard work now is done. Press EXIT and then DRAW (F6). It should look like figure 7.

Part 3 - Further Exercises
Try these functions such as:

Hope the lesson has been helpful and that you get some ideas from it.

Marty Schmude