Texas Instruments TI-82 Getting Started page 11

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Figure I.25: Two semicircles

If your range were set to the standard viewing window, your graph would look like Figure I.26. Now this

does not look like a circle, because the units along the axes are not the same. This is where the square

viewing window is important. Press ZOOM 5 and see a graph that appears more circular.

Figure I.27:

horizontal

Technology Tip: Another way to get a square graph is to change the range variables so that the value of

Ymax - Ymin is approximately times Xmax - Xmin. For example, see the WINDOW in Figure I.27 and

the corresponding graph in Figure I.28. This method works because the dimensions of the TI-82's display

are such that the ratio of vertical to horizontal is approximately

The two semicircles in Figure I.28 do not connect because of an idiosyncrasy in the way the TI-82 plots

a graph.

Back when you entered

some keystrokes. Try this by going back to the Y= menu and pressing

Then press CLEAR (-) 2nd Y-

I.2.5 TRACE: Graph

clear any other functions in the Y= screen.) Press any of the arrow keys

move from the center of the viewing window. The coordinates of the cursor's location are displayed at the

bottom of the screen, as in Figure I.29, in floating decimal format. This cursor is called a free-moving cursor

because it can move from dot to dot anywhere in the graph window.

Technology Guide

Graphing

vertical

and

1 1. The graph should be just as it was before.

VARS

from Section I.2.2 in the standard viewing window. (Remember to

−10

Figure I.26: Circle's graph – standard WINDOW

−12

Figure I.28: A "square" circle

you could have entered

−10

−8

-Y

and saved

to move the cursor down to

, ,

and see the cursor

I-11