HP HP-35 - Page 29

18
Although logarithms were origina ll y ured to speed multi-
plication
and division, they have partIcular significance in
scientific and engineering problems. There is. for example,
a logarithmIc relatIonshIp belwtlen alti
tude and barometric
pressure. Suppose you wish 10 use an ordinary barometer
as an alIi meIer. Afler measuring the sea level pressure
(30 inches of mercury) you climb unlil Ihe barometer in-
dicates
9.4 inches of mercury. How hIgh are you? Allhough
Ihe e~act relatIonship of pressure and alt i tude IS a function
01 many lactor'$, a reas onab le appro~imalion is given by:
Press
25000
IlmIl
30
IlmIl
9.4
;;
l1li
£I
30
Altllude (teet) • 25,000 In ---
Pressure
""
Comments
2500 0 .
25000.
30 .
30
9
4
Pr essure at altitude
3.
1 9 1 4 89362
1 60 4 87693
290 12 19233
Altitude
[We SUSpe.c1 thaI you may be on Mt. Everesl (29.028 feet))
Your
Hp·35 compules trigonometric f unctions of angles
measured
on degrees and decimal fractions of a degree.
E~ ample! Find sin 30.5 °, cos 150", Ian _25.6°.
Press So, Comments
30.5 30 . 5
5075383628
sm 30 .5
o