TI-92 -- Looking for Periodicity
Sunspots

You may want to look at the TI-92 help modules below for this module.

• Making a Table of Values for a Sequence
• Graphing a Sequence
• Working with lists

The first thing you need to do is to download the data for the average daily number of sunspots from 1749 to 1976 to your TI-92. If your workstation has the TI-Graph Link cable and software then the following two steps will do the job.

• Click here to launch the TI-92 Graph Link program with the data. Then follow the usual instructions to download the program sundata to your TI-92.

• From the home screen type sundata() and then press ENTER. The data is now stored in the list sunspot in your TI-92.

You can look at the data following the usual intsructions for Making a Table of Values for a Sequence. Be sure that the graphics mode is set to SEQUENCE. The screen below shows how the TblSet screen should look.

The screen below shows how the WINDOW screen should look.

The screen below shows how the Y= screen should look.

The screen below shows the TABLE screen with the first eight data points.

Next we want to look at this data graphically. You may want to consult the TI-92 help module Graphing a Sequence

Review the WINDOW screen above and make sure that the graphing mode is set to SEQUENCE. Turn off the u1 plot in the Y= screen by arrowing to u1 and pressing F4 so that the Y= screen looks like the screen below.

Then arrow down to u2 and select the line style for the u2 graph from the style menu (F6) as shown in the screen below.

Finally, press GRAPH to see the data graphically.