Plot 1, ..., Plot 3 switches on TI-83 calculator

Question

My student has a TI-83 (I think - it is black, and newer than mine, and I have a TI-82), and she asked me what the three switches were, those at the top of the function list screen (where you input what is to become a graph) - the switches labeled Plot1, Plot2, and Plot3?

I told her 1) I don't know, and 2) I associate "plotting" with the practical side of drawing a graph from a data set, placing the spots to be joined by the function curve.

We did not understand it by experimenting, either.

I will email her any answers, so don't be shy to elaborate a couple of paragraphs on the purpose and usage of those switches.

Cheers

Answer 1

My recommendation would be "go directly to the source":

• See, e.g., TI-83 Guide Book
• or visit the eduction site for TI-83 Plus/silver-edition to view the features, applications, and available "downloads", if your student has the "plus" model.

See also this "feature tutorial" for graphic, step-by-step instructions for using various features of the TI- 83, and/or how to use them.

Answer 2

From pages 231-238 of the TI-83 UK manual, I have concluded that my intuition was correct: plotting is about drawing graphs, manually from a data set (although the calculator helps).

It is possible to plot six different diagrams: the data set(s) are interpreted differently for different diagrams.

The most simple example, perhaps, is a filled curve (a graph). Coordinates - the plots - are extracted from two lists, with x positions in one, and y positions in the other.

So, type the coordinates:

{1, 2, 3}->L1

{2, 4, 6}->L2

Then press [STAT PLOT].

An overview is shown. It is possible to have three plotted diagrams at work, at the same time. To experiment with the first (Plot1), press [1] or [ENTER].

Now, some details are shown:

• On/Off (draw the diagram or not - this can also be set by marking the Plot1 switch in the [Y=] screen)
• Type (for a curve that passes through the plots, pick the middle icon on the top line)
• Xlist (the x:es, set to L1 - use the specific one-character key)
• Ylist (the y:s, set to L2)
• Mark (how to show the plots when drawn: I suppose it doesn't really matter unless you have more than one diagram, and you like to keep them apart)

So, the coordinates are (x, y) = (1, 2), (2, 4), and (3, 6)!

Example when to use: Say that you have a data set of observations, and you wish to illustrate how close (or not close...) it follows a math function. Plot the data set, enable it, enter the function, draw, and compare.