Texas Instruments Titanium TI-89, User Manual

Page: 396 / 977

3D Graphing 393
Note:
These examples use the same x, y, and z Window variable values as a
ZoomStd
viewing cube. If you use
ZoomStd
, press Z to look down the z axis.
Notes About Implicit Plots
For an implicit plot:
• The
ncontour
Window variable has no affect. Only the
z=0
contour is drawn,
regardless of the value of ncontour. The displayed plot shows where the implicit form
intersects the xy plane.
• You can use the cursor keys to animate the plot.
• You cannot trace (
…
) the implicit plot itself. However, you can trace the unseen wire
frame graph of the 3D equation.
• It may take awhile to evaluate the equation initially.
• Because of possible long evaluation times, you first may want to experiment with
your 3D equation by using Style=WIRE FRAME. The evaluation time is much
shorter. Then, after you’re sure you have the correct Window variable values, set
Style=IMPLICIT PLOT.
8
Í
Example: Implicit Plot of a More Complicated
Equation
You can use the IMPLICIT PLOT graph format style to plot and animate a complicated
equation that cannot be graphed otherwise. Although it may take a long time to evaluate
such a graph, the visual results can justify the time required.