Texas Instruments PLUS TI-89 - Manual (Page 174)

Chapter 10: 3D Graphing 157
10_3D.DOC TI-89/TI-92 Plus: 3D Graphing (English) Susan Gullord Revised: 02/23/01 11:00 AM Printed: 02/23/01 4:22 PM Page 157 of 22
Use 3 to set Graph = 3D before you define equations or set
Window variables. The Y= Editor and the Window Editor let you
enter information for the current
Graph mode setting only.
The Y= Editor maintains an independent function list for each Graph
mode setting. For example, suppose:
¦ In FUNCTION graphing mode, you define a set of y(x) functions.
You change to 3D graphing mode and define a set of z(x,y)
equations.
¦ When you return to FUNCTION graphing mode, your y(x) functions
are still defined in the Y= Editor. When you return to 3D graphing
mode, your z(x,y) equations are still defined.
Because you can graph only one 3D equation at a time, display styles
are not available. On the Y= Editor,
Style toolbar menu is dimmed.
For 3D equations, however, you can use:
ƒ
9
— or —
TI
-
89: ¥ Í
TI
-
92 Plus : ¥ F
to set the Style format to WIRE FRAME or HIDDEN SURFACE . Refer
to “Changing the Axes and Style Formats” on page 165.
Differences in 3D and Function Graphing
This chapter assumes that you already know how to graph y(x)
functions as described in Chapter 6: Basic Function Graphing.
This section describes the differences that apply to 3D
equations.
Setting the
Graph Mode
Defining 3D
Equations on the
Y= Editor
Tip: You can use the Define
command from the Home
screen (see Appendix A) to
define functions and
equations for any graphing
mode, regardless of the
current mode.
Selecting the
Display Style
You can define 3D
equations for z1(x,y)
through z99(x,y).