Self-selecting Hyperbolic functions for the HP-25/25C

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The program presented below will calculate the Hyperbolic Trig functions (Sinh, Cosh, Tanh) on the HP-25. It was written by James Davidson and appeared in the V3N5P11 issue of the PPC Journal (May 1976). Thanks to James!

This program definately DOES violate my stated objectives for putting programs on my page. Why is it here then? Because the programming technique James used deserves to be seen.

This program is called self-selecting because of how you use it.

You key in the angle you need, then perform the corresponding normal trig function on the angle, then press R/S. The program determines which normal trig function you performed and performs the complementary hyperbolic trig function. Quite neat, actually!

Examples: 1) Find the Sinh of 10 degrees: 10, f SIN, R/S. Display shows 11013.233. 2) Find the Cosh of 5 degrees: 5, f COS, R/S. Display shows 74.209949. 3) Find the Tanh of 0.867 degrees: 0.867, f TAN, R/S. Display shows 0.699847.

Program Listing: Email if you have any questions.
```Line      Instruction  Keycode
01         f LASTX      14 73
02         f SIN        14 04
03         f X = Y      14 71
04         GTO 21       13 21
05         RDN          22
06         f LASTX      14 73
07         COS          14 05
08         f X = Y      14 71
09         GTO 28       13 28
10         f LASTX      14 73
11         g e^x        15 07
12         g x^2        15 02
13         1            01
14         -            41
15         ENTER        31
16         ENTER        31
17         2            02
18         +            51
19         /            71
20         GTO 00       13 00
21         f LASTX      14 73
22         g e^x        15 07
23         ENTER        31
24         g 1/X        15 22
25         -            41
26         2            02
27         GTO 19       13 19
28         f LASTX      14 73
29         g e^x        15 07
30         ENTER        31
31         g 1/X        15 22
32         +            51
33         GTO 26       13 26
```

That's it!
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