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Step4. Because I know that part (iv) of the
question requires me to re-use these
extremum values in an integration
(which I would like to be as accurate
as possible), I am going to ‘save’ the
extremum value just found. I change
into the
HOME
view and store it as
shown in memory
A
.
Note
: You MUST store the point of
interest before moving the cursor in
the PLOT view. As soon as the cursor
moves its new position over-writes the
extremum value. If you want the y
coordinate, just evaluate
F(X)
.
Now use the FCN - Extremum tool
again to find and store the x coordinate
of the second turning point into
memory B.
Step 5. The
PLOT
view shows that part of the
area we require for part (iv) is
negative, so we need to know the x
intercept between the two turning
points. Fortunately we know from Step
2 that it is the point (2,0). If we did not
know this already, then we could use
the
menu again, retrieving this
time from the
VAR
menu the variable
called ‘
Root
’ and perhaps storing that
into memory
C
. We will evaluate the
integral in the
HOME
view where you
can use the accurate values you stored in Step 4. It needs to be
done in two parts and added (subtracted actually to reverse the sign
of the negative part). This is shown right, with the
key having
been used to add the values.