HP 25 User Manual

Function Keys 63
Example 2: Convert polar coordinates (S, 120°) to rectangular
coordinates .
(X,y)
r=8
Press Display
m ~
1 0.00
120mimJS
1 8.
y
x
Specifies degrees mode .
(Assumes no results remain
from previous
example .)
Polar coordinates (! and r
placed in Y - and X-registers ,
respectively.
a ~ 1 -4 . 00 x-coordinate .
EiD 1 6.93 1 y-coordinate.
Logarithmic and Exponential Functions
Logarithms
The H P-25 computes both natural and common loga rithms as
well
as their inverse functions (antilogarithms):
a lli!J is loge (natural log) . It take s the log of the value in the
X-register to base e (2.7IS ... ) .
m ~ is antilog
,
. (na tur al antilog). It raises e (2.7IS ... ) to
the
power of the value in X-register. (To display the
value
of e, pres s I m ~ .)
a [IQ9J is loglo (common log). It compute s the log of the value
in the X-register to ba se 10.
m ~ is antilog
lo
(common antilog). It ra is es 10 to the power
of the value in the X-register.
Example 1: The 1906 San Fr ancis co ea rthquake , with a magni-
tude of S.25 on the Richter Scale is es timated to be 105 times
greater than the Nic aragua quake of 1972. What would be the
magnitude of the la tter on the Richter Scale? The equation is
M ., 105
RI = R2 - log M; = S.25 - (log -1-)

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