Texas Instruments TI-82 Keystroke Manual page 43

38 Calculator Keystroke Guide
displayed on the graphing window. Ymin indicates the value of y at the very bottom of the
graphing window when it is displayed. On the Standard (default) viewing window Ymin = −10.
Ymax represents the largest value of y to be displayed on the graphing window. Ymax indicates
the value of y at the very top of the graphing window when it is displayed. On the Standard
(default) viewing window Ymax = 10. Yscl indicates the distance between tick marks on the y-
axis. On the Standard (default) viewing window Yscl = 1. Xres indicates how often the calculator
will compute and plot a point on the graph. Generally, Xres should be set at the value 1 and left
that way. Unless a specific situation calls for Xres to be changed, you should assume from
now on that the value of Xres should be 1.
In summary, when you have set the Window settings to the Standard (default) values, the
screen should display the following:
Xmin=-10
Xmax=10
Xscl=1
Ymin=-10
Ymax=10
Yscl=1
Xres=1
To see this Standard (default) viewing window for graphs, display the Graph screen by
pressing GRAPH. Your screen should display a graphing window like the one shown in Figure
2.10 on page 86 of your text.
To see another graphing window, press the WINDOW key, change the settings as shown below,
and then press GRAPH again to see this different graphing window:
Xmin=-4
Xmax=12
Xscl=2
Ymin=-50
Ymax=80
Yscl=25
The left edge of the screen is at x = −4, and the tick marks on the x-axis are 2 units apart, so the
first tick mark to the right of the origin on the x-axis represents 2, the next one to the right of it
represents 4, the one after that 6, etc. On the y-axis the mark at the very bottom of the screen
represents −50, and the tick marks on the y-axis are 25 units apart, so the first mark above the
origin on the y-axis represents 25, the next one above it represents 50, and the next represents 75.
Since the value of y at the very top of the screen is 80 (Ymax), notice that the y-axis extends just a
bit above the tick mark representing 75.
There is a second way to produce the Standard (default) viewing window on your calculator.
Any time you wish to return the Window settings to the Standard (default) settings, just press the
ZOOM key and press 6 to select the Standard viewing window (ZStandard). (From now on, this