Texas Instruments TI-85 - Manual (Page 8)

B-8 TI-85/TI-86 Graphing Calculators
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1.1.4 AUTOMATICALLY CHANGING THE VIEW OF THE GRAPH If your view
of the graph is not good or if you do not see the graph, change the view using the built-in
autoscaling feature of your calculator. This option will automatically find a view to see a l l
the functions that you have turned on in the graphing list.
Be sure the function you are graphing, y = 1000(1 + 0.05) x , is entered in the y1 location of t h e
y(x)= list. (Delete all other functions that may be entered in other locations.) Before doing
what follows, access the graphics menu with GRAPH .
To access the range on the TI-85 (called the window on
the TI-86), press F2 . Set xMin to 0 and xMax to 10. (It does
not matter what values are set in the yMin and
yMax positions.) Press F3 ( ZOOM ) MORE F1 ( ZFIT ) .
Your calculator automatically sets a vertical view
(based on the
xMin and xMax you set) and draws a
graph of the function.
1.1.5 TRACING You can display the coordinates of certain points on the graph by tracing.
The x-values shown when you trace depend on the horizontal view that you choose, and t h e
y-values are calculated by substituting the x-values into the equation that is being graphed.
With the graph on the screen, press F4 ( TRACE )
and use to move the trace cursor to the right
and to move the trace cursor to the left.
The number 1 in the upper right hand corner of the
screen tells you that you are tracing on the equation
in
y 1 .
Trace past the edge of the screen and notice that even
though you cannot see the trace cursor, x and y values
of points on the line are still displayed at the bottom
of the screen. Also notice that the graph scrolls to the
left or right as you move the cursor past the edge of
the current viewing screen.
1.1.6 ESTIMATING OUTPUTS You can estimate outputs from the graph using TRACE . I t
is important to realize that such outputs are never exact values unless the displayed x-value
is identically the same as the value of the input variable.