Chapter 8: Polar Graphing 133
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 133 of 6
Chapter 8:
Polar Graphing
Preview of Polar Graphing....................................................................134
Overview of Steps in Graphing Polar Equations................................135
Differences in Polar and Function Graphing......................................136
This chapter describes how to graph polar equations on the
TI-89 / TI-92 Plus. Before using this chapter, you should be familiar
with Chapter 6: Basic Function Graphing.
Consider a point (x,y) as shown below. In a polar equation, the
point’s distance (r) from the origin is a function of its angle (q)
from the positive x axis. Polar equations are expressed as r = f(q).
r
θX
Y
y
x(x,y)
To convert between rectangular (x,y)
and polar coordinates (r,q):
x = r cos qrñ= xñ+ yñ
y = r sin qq
= ìtan–1 x
y +
sign(y)øp
2
Note: To find q, use the
TI-89 / TI-92 Plus function angle(x+iy),
which automatically performs the
calculation shown above.
You can view the coordinates of any point in either polar (r,q) or
rectangular (x,y) form.
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