HP 25

formula to calculate the great circle distance that Odysseus
must sail in order to court her.
Distance = COS- I [ sin (LAT ,) sin (LAT
d
)
+
cos (LAT,) cos (LAT
d
) cos
(LNG
d
-
LNG
s
) ] x 60.
Where LAT s and LN G
s
= latitude and longitude of the
source (Tristan
da Cunha).
LATd and
LNG
d
= latitude and longitude of the
destination.
Solution: Convert a ll degrees, minutes, seconds entr ies into
decimal degrees as you key them
in . The equation for the great
circle distance from Tristan da Cunha to the nearest inhabited
land is:
Distance = COS-I [ s in (37°03') sin (15 °55') +
cos (37° 03') cos ( 15 °55') cos (5 °43'W - 12 ° 18 'W) ] x 60
Press
Display
0. 00
0.00
5.43 11 @ 5.72
12. 18 II @ El 1;= - ~ 6. ~ 58 ~ ===;
O ~ 1 0. 99
15 . 55 1I @ 1lmJ1 F= I = 1 5 == . 9 ~ 2 = =:
o ~ 1 0.96
~ === = =:
o i=1 = 0 = . 9 = 6 ==~
37.0311@ 1lmJ0 1 37 . 05
O ~ 1 0. 80
o 1 i== 0. ~ 76 ~~
1m 00 ~ I 0. 60
_ 1 0 ~ :=1 =0.=2=7 ====i
o i=1 = 0 . = 1 = 7 == ~
El 1 0.93
II ~ ~I ~ 2 ~ 1 ~ .9 =:' 2 = =:::;
60
0 1 1315.41
Display mode is set.
(Assumes no results remain
from previous example.)
Sets decimal degree mode for
trigonometric functions.
Distance in nautical miles that
Odysseus must sa il to visit
Penelope.