Texas Instruments TI-89 Titanium User Manual

3D Graphing 388
• 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,
display the Graph Formats dialog box and set Style=CONTOUR LEVELS or WIRE
AND CONTOUR.
8 Í
Example: Contours of a Complex Modulus Surface
The complex modulus surface given by z(a,b) = abs(f(a+bi)) shows all the complex zeros
of any polynomial
y=f(x).
Example
In this example, let f(x)=x
3
+1. By substituting the general complex form x+yi for x, you
can express the complex surface equation as z(x,y)=abs((x+yi)
3
+1).
1. Use 3 to set
Graph=3D.
2. Press 8#, and define the equation:
z1(x,y)=abs((x+yù
i)^3+1)
3. Press 8$, and set the Window
variables as shown.

Texas Instruments TI-89 Titanium Specifications

General

Display Type	LCD
Display Resolution	160 x 100 pixels
CPU	Motorola 68000
CPU Speed	16 MHz
RAM	256 KB
Flash ROM	2.7 MB
Programming Language	TI-BASIC, Assembly
Power Source	4 AAA batteries
Connectivity	I/O port
Dimensions	7.5 x 3.5 x 1 inches