Texas Instruments PLUS TI-89 - Manual (Page 420)

Chapter 23: Activities 403
23ACTS.DOC TI-89/TI-92 Plus: Activities (English) Susan Gullord Revised: 02/23/01 1:24 PM Printed: 02/23/01 2:20 PM Page 403 of 26
6. In the Y=Editor, press:
TI - 89: ¥ Í
TI - 92 Plus: ¥ F
and set the Graph Format
variables to:
Axes= ON
Labels= ON
Style=
HIDDEN SURFACE
7. Graph the modulus surface.
The 3D graph is used to
visually display a picture of the
roots where the surface
touches the xy plane.
8. Use the Trace tool to explore
the function values at x=1 and
y=0 .
9. Use the Trace tool to explore
the function values at x=0 and
y=1 .
10. Use the Trace tool to explore
the function values at x=0 and
y= ë 1 .
Note that zc is zero for each of the function values in steps 7–9. Thus,
the complex zeros 1,ë i, i of the polynomial x т м x ñ +x ì 1 can be
visualized with the three points where the graph of the modulus
surface touches the xy plane.
Note: Calculating and
drawing the graph takes
about three minutes.
Summary