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Integration: The definite integral using PLOT variables
As was discussed earlier, when you find roots, intersections, extrema or
signed areas in the
PLOT
view, the results are stored into variables for
later use.
Root
to find the x intercept of
For example, if we use
f x
( )
=
x
2
−
2
then the result is stored into a variable called
Root
, which
can be accessed anywhere else. Similar variables called
Isect
,
Area
,
and
Extremum
are stored for the other
tools.
You can access these names by typing them in using the
ALPHA
key, or
by using the
VARS
key. Press
VARS
and you will see a list of the
HOME
variables.
(not the APLET button on the
keyboard), then the display changes to show the variables specific to
whatever aplet you are currently using. Those shown right are for the
Function aplet and the group of
Plot FCN
variables is shown.
If you press
SK2
, labeled
tag is currently selected (showing as
) and
this means that when you press
If you look at the screen shot you will see that the
the name of the variable will be pasted into what ever view you were
using when you pressed the
VARS
key. Pressing the
screen key will cause the
value
of the variable to
be pasted instead. There is no effective difference in most situations.
This can be very useful in finding areas, as you will see in the example on the following page.
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