Texas Instruments TITANIUM TI-89 - Manual (Page 402)

3D Graphing 402
• 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 Example: Contours of a Complex Modulus Surface Example: Contours of a Complex Modulus Surface 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 Example Example Example
In this example, let f(x)=x
3
+1. By substituting the general complex form x+y i 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+y ù
i )^3+1)
3. Press 8 $, and set the Window
variables as shown.