User Manual

14 Section 1: Using _ Effectively
14
First convert 5° 18'S to decimal degrees (press 5.18”|À), obtaining −5.3000
(using •4 display mode). (Southern latitudes are expressed as negative numbers for
calculation purposes.)
The solution to Coulerre's problems is the value of t satisfying
−5.3000 = a
4
t
4
+ a
3
t
3
+ a
2
t
2
+ a
1
t + a
0
.
Expressed in the form required by _ the equation is
0 = a
4
t
4
+ a
3
t
3
+ a
2
t
2
+ a
1
t − 2.8806
where the last, constant term now incorporates the value of the declination.
Using Horner's method, the function to be set equal to zero is
f(t) = (((a
4
t + a
3
)t + a
2
)t + a
1
)t − 2.8806 .
To shorten the subroutine, store and recall the constants using the registers corresponding to
the exponent of t.
Keystrokes
Display
= -
PrError
Clears calculator’s memory.
*
−
0.0000
|¥
000-
Program mode.
´bA
001-42,21,11
l4
002- 45 4
*
003- 20
l3
004- 45 3
+
005- 40
*
006- 20
l2
007- 45 2
+
008- 40
*
009- 20
l1
010- 45 1
+
011- 40
*
012- 20
l 0
013- 45 0
+
014- 40
|n
015- 43 32
*
This step is included here only to ensure that sufficient memory is available for the examples that follow in this handbook.