Integer - Texas Instruments TI-82 Keystroke Manual

keystroke sequence will be denoted ZOOM 6.) The graphing window will then be displayed with
the Standard (default) settings. To verify that the calculator has changed the Window settings to
the Standard (default) values, press the WINDOW key to view the settings. Any time you wish to
return to the Home screen from any of these other screens, just press 2nd [QUIT].
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17 Integer

Sometimes we want to have a graphing window that will display integer coordinates, rather than
the lengthy decimal coordinates that often arise with other graphing windows. Such a viewing
rectangle is called an Integer graphing window. Although an Integer graphing window may be
produced beginning from any set of Window settings, press ZOOM 6 to display the Standard
(default) viewing window. Press the ZOOM key once more. Notice the arrow pointing downward at
the bottom of the screen next to choice 7. That arrow indicates that the Zoom menu has more
items in it which may be viewed by pressing the Down Arrow key to scroll the menu downward.
Press the Down Arrow key several times (or hold it down) until the highlight is on 7. Now press
the Down Arrow key once more. Notice that the menu has scrolled downward to reveal a choice 8,
which is ZInteger. Choose ZInteger either by pressing 8 or by moving the highlight to 8 and
pressing ENTER. The calculator will display the as-yet-unchanged graphing window, and there
will be a set of coordinates displayed at the bottom of the screen which represent the coordinates
of a small free-moving cursor, which may be a bit hard to see, since it is at the origin. (You may
see a blinking pixel at the origin.) Press the Up Arrow and Right Arrow keys a few times so that
you get a better look at this free-moving cursor. This cursor should be moved to approximately
the coordinates of the point you want to have in the center of the screen after the calculator creates
the Integer graphing window. If you wish to have the point (7,5) at the center of the Integer
graphing window, then move this free-moving cursor to a point as close to (7,5) as possible. That
is, move the cursor with the arrow keys until the coordinates displayed at the bottom of the screen
are as close as you can get them to x = 7 and y = 5. (From the Standard graphing window, the
closest you can come is probably x = 7.0212766 and y = 4.8387097.) Press ENTER to produce the
Integer graphing window centered at (7,5). Press the Right Arrow key to produce a larger free-
moving cursor one pixel to the right of the center of the screen. (See 19 Cursor for more details
about this cursor.) Note that the coordinates of the cursor are (8,5). Press the Left Arrow key to
return to the center of the screen, which is at (7,5). Press other arrow keys and note that every
time you press the Left Arrow key or the Right Arrow key, the value of x remains an integer and
changes by 1. Likewise, every time you press the Down Arrow key or the Up Arrow key, the
value of y remains an integer and changes by 1. You may want to look at the Window settings to
see how things have been changed.
Press the GRAPH key again to display the graphing window. If you want to change the
coordinates of the center to some other point, such as the origin (0,0), press ZOOM 8, move the
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