Texas Instruments TITANIUM TI-89 User Manual

Page 399

3D Graphing

399

How Are Z Values Determined?

You can set the ncontour Window variable (

8 $) to specify the number of

contours that will be evenly distributed along the displayed range of z values, where:

ncontour=5

and you use the standard viewing window (

zmin=

and

zmax=10

) , the

increment is 3.333. Five contours are drawn for z=L6.666, L3.333, 0, 3.333, and 6.666.

Note, however, that a contour is not drawn for a z value if the 3D graph is not defined at
that z value.

increment =

The z values for the contours are:

zmin + increment
zmin + 2(increment)
zmin + 3(increment)

zmin + ncontour(increment)

zmax zmin

–

ncontour 1

---------------------------------

The default is 5. You
can set this to 0
through 20.