Texas Instruments PLUS TI-89 - Manual (Page 151)

134 Chapter 8: Polar Graphing
08POLAR.DOC TI-89/TI-92 Plus: Polar Graphing (English) Susan Gullord Revised: 02/23/01 10:57 AM Printed: 02/23/01 2:14 PM Page 134 of 6
Steps
³
TI-89
Keystrokes
›
TI-92 Plus
Keystrokes Display
1. Display the MODE dialog box.
For Graph mode, select POLAR .
For Angle mode, select RADIAN .
3
B 3
D D D B 1
¸ 3
B 3
D D D B 1
¸
2. Display and clear the Y= Editor.
Then define the polar equation
r1( q ) = A sin B q .
Enter 8 and 2.5 for A and B,
respectively.
¥ #
ƒ 8 ¸
¸
8 2 W 2 . 5
¥ Ï d ¸ ¥ #
ƒ 8 ¸
¸
8 W 2 . 5 Ï
d ¸
3. Select the ZoomStd viewing
window, which graphs the
equation.
• The graph shows only five rose
petals.
− In the standard viewing window,
the Window variable
q max = 2 p .
The remaining petals have q
values greater than 2 p .
• The rose does not appear
symmetrical.
− Both the x and y axes range from
ì 10 to 10. However, this range is
spread over a longer distance
along the x axis than the y axis.
„ 6 „ 6
4. Display the Window Editor, and
change q max to 4 p.
4 p will be evaluated to a number
when you leave the Window Editor.
¥ $
D
4 2 T ¥ $
D
4 2 T
5. Select ZoomSqr , which regraphs
the equation.
ZoomSqr increases the range along
the x axis so that the graph is shown
in correct proportion.
„ 5 „ 5
6. You can change values for A and
B as necessary and regraph the
equation.
Preview of Polar Graphing
The graph of the polar equation A sin B q forms the shape of a rose. Graph the rose for
A=8 and B=2.5. Then explore the appearance of the rose for other values of A and B.