HP 39gs Master Manual page 355

viii. We can see symmetry visually if the function is graphed and the aplet best suited to this is the Parametric
aplet. When a function is sent to the Parametric aplet the real part is sent to the x and the imaginary part
to the y component of the parametric equation selected.
On the screen, define an expression X 1( T
and changing back to large font too.
SHIFT SHIFT ALPHA CLEAR
ALPHA X 1 ( ALPHA T
ALPHA Y 1 ( ALPHA T SHIFT
Now store to the aplet using the
PLOT ENTER ENTER
Note:
The reason that we used capital
case here is because that is the variable used by the
t
Parametric aplet.
We now change out of the CAS and activate the
Parametric aplet in the usual fashion.
do you should see the screen shown right. Each of
these expressions needs to be simplified before
graphing or it will significantly slow down the
process. Highlight each in turn and press the
screen button. Then press the
Calculator Tip
Although and were chosen as names for the functions defined
X1 Y1
earlier this has no relevance for the pasting into the Parametric aplet.
They could just as easily have been defined as
However, it is suggested that you not define a function as simply
This is because is defined as the current variable by defau
X
means that the contents of your function def
soon as you perform any operation that uses the current variable.
+ SHIFT 1
button on the keyboard, choosing
PLOT
T
When you
button.
Fred(t)
ini tion will be purged as
) + ⋅ 1( i Y T ) which can be sent to the aplet, evaluating it
ENTER
instead of lower
355
and .
Jim(t)
.
X(t)
lt and this
in the Parametric aplet.
X1,Y1