HP 25 User Manual

60 Function Keys
Hours, Minutes, Seconds
The I +H.MS 1 (to hours, minutes, seconds) key converts decimal
hours to the format of hours , minutes and seconds . To see the
digits for
seconds, you should specify FIX 4 display format.
Forexample, to convert 12.56 hours to hours, minutes, seconds:
Press Display
12.56
D ~ 4
D I +H.MS I
1 12.56
112. 5600
1 12.3336
Decimal hours.
Sets display format.
This is read as 12 hours, 33
minutes, 36 seconds .
Conversely, the EEl (to decimal hours) key is used to change
hours, minutes, seconds into decimal hours. For example, to
convert 12 hours , 33 minutes, 36 seconds back into decimal
hours:
Press Display
112.5600
Decimal hours.
Hours to hours, minutes, seconds conversion is accurate to 10 -
5
decimal hours .
The EEl and 1 +H.MS I keys also permit you to change degrees,
minutes, seconds to decimal degrees , and vice versa.
For example , to change 137 °45' 12" to decimal degrees:
Press
Display
137.4512
D EE]
1137.4512
1137.7533
Decimal degrees.
The conversion is important because trigonometric functions in
the H P-25
operate on angles in de cimal degrees, but not in
degrees, minutes, sec onds . In order to calculate any trigono-
metric functions
of an angle given in degrees , minutes, seconds,
you must first convert the angle to decimal degrees .
Example: Lovesick sailor Osc ar Odysseus dwells on the island
of Tristan da Cunha (37° 03 ' S, 12 °18'W), and his sweetheart,
Penelope, lives on the nearest island. Unfortunately for the
course of true love, however, Tristan da Cunha is the most
isolated
inhabited s pot in the world. If Penelope lives on the
island
of St. Helena (15° 55'S, 5° 43'W) , use the following

HP 25 Specifications

General

Power Source	Rechargeable battery pack
Programming Steps	49
Release Year	1975
Functions	Trigonometric, logarithmic, statistical
Type	Scientific
Dimensions	148 x 80 x 14 mm