# HP -28S Manual Page 86

• R- P
(rectangular-to-polar)
converts a complex number in rectangu-
lar notation
(x,
y)
to polar notation
(r,
0).
• P-R
(polar-to-rectangular)
converts a complex number in polar no-
tation
(r,
0)
to rectangular notation
(x,
y).
• ABS
(absolute value)
returns
r
for a complex argument
(x, y).
• NEG returns (-
x, -
y) for a complex argument
(x,
y).
• ARG returns 0 for a complex argument
(x, y).
Note that only P-R interprets a complex number as polar coordinates;
all other functions-arithmetic, trigonometric, logarithmic, hyperbolic,
and so on-interpret a complex number as rectangular coordinates.
Remember this important rule:
Any complex number in polar coordi-
nates must be converted to rectangular coordinates before you can use it
in a calculation.
As an example of arithmetic with polar coordinates, suppose you
travel 2 miles at a bearing of 36°, then 3 miles at a bearing of 65°.
What is the resulting distance and bearing, calculated to two decimal
places?
Select Degrees angle mode and FIX 2 number display .
1
MODE
I
DEG
2
F I X
3:
(25. 001.35. 00)
2:
(0.0~,2.00)
1:
(1.57,-1.32)
RillIiD_o::aGm~
Enter the first distance and bearing.
~----------~~~~~~~
CD
2
GJ
36
2:
(0.00,2.00)
1:
(1.57,-1.82)
Convert to rectangular coordinates .
1
COMPLX
II
NEXT
I
P+R
(2,360
RillIiD_o::aGm~
3:
(0.00,2.00)
2:
(1.57 -1.32)
1 :
(
1.
62,
1.
18)
DlIIGmlI:lIBCIBI'i1B_
Enter the second distance and bearing.
CD
3
GJ
65
=2-: -----:-( -:-1. - =5=7"""1. --1"-.-=3-=-2""")
1 :
(
1. 6<:::, 1. 18)
(3,650
DlIIGmlI:lIBCIBI'i1B_
6: Complex-Number Functionns
85  