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Advice to buy an HP
04-19-2015, 09:15 PM
Post: #38
RE: HP-80
Thomas and others,
Regarding Logs and Anti-Logs on the HP-80

To get a common logarithm or natural logarithm, use the following keystrokes:

900 i , 1 PV, (number) FV (where "number" is the value you want the logarithm for). Then pressing "n" leaves the common log in X-Register and natural log (Ln) in Y-register.

So, for the LOG and Ln of 256, you use these keystrokes, IN EXACTLY THIS ORDER:
900 i, 1 PV, 256 FV. Press n to get the answer: 2.408240 is the LOG. Press X<>Y to show the Ln of 5.545177.

For logarithms of other bases, you would use enter the base:
Press Save, 1 - 100 X, then i and 1 PV, the number and FV and press n to get the result. So for a logarithm base 2 of 256, you take 2-1 * 100 ( or simply enter 100) and press i, 1 PV 256 FV and pressing n will yield 8. The Ln of 256 will still be in the Y-Register.

Later financial models do NOT leave then natural log in Y, but will leave the common log in X per the above instructions. For models that use the TVM5, (starting with the HP-92) the 1 in the PV register needs to be changed to negative.

Common (Base 10) anti-logs are simple. Just enter 10 Save and the number and press Y^X to get the antilog of the number.

For Base e, you first need to compute e (2.718281828), by taking 1.000001 to the power of 1 million, then enter the number and Y^X. This only works on the earlier calculators. During the Woodstock era, I think before the HP-67 came out, internal calculations became more precise, so this trick will not produce the correct value for e on later machines. This is fairly easy to remember: Just take 1, the decimal point, add 5 zeroes, and another 1, SAVE, 1000000 and Y^X. Then enter the value you want the anti-log of and Y^X.

Regards,
Bob
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Messages In This Thread
Advice to buy an HP - Cancuino - 04-15-2015, 09:25 PM
RE: Advice to buy an HP - d b - 04-15-2015, 10:23 PM
RE: Advice to buy an HP - Cancuino - 04-15-2015, 10:36 PM
RE: Advice to buy an HP - walter b - 04-16-2015, 07:42 AM
RE: Advice to buy an HP - Cancuino - 04-16-2015, 08:01 AM
RE: Advice to buy an HP - Les Bell - 04-16-2015, 11:47 PM
RE: Advice to buy an HP - Les Bell - 04-17-2015, 01:33 AM
RE: Advice to buy an HP - RayAtHP - 04-15-2015, 10:37 PM
RE: Advice to buy an HP - Jlouis - 04-15-2015, 11:08 PM
RE: Advice to buy an HP - Cancuino - 04-15-2015, 11:14 PM
RE: Advice to buy an HP - Jlouis - 04-15-2015, 11:39 PM
RE: Advice to buy an HP - d b - 04-16-2015, 12:53 AM
RE: Advice to buy an HP - TASP - 04-16-2015, 01:18 AM
RE: Advice to buy an HP - bshoring - 04-16-2015, 07:25 AM
RE: Advice to buy an HP - TASP - 04-16-2015, 01:21 PM
RE: Advice to buy an HP - Don Shepherd - 04-16-2015, 01:57 PM
HP-80 - bshoring - 04-16-2015, 10:04 PM
RE: Advice to buy an HP - TASP - 04-17-2015, 05:09 PM
RE: Advice to buy an HP - Omar Deen - 04-16-2015, 03:37 AM
RE: Advice to buy an HP - Sukiari - 04-16-2015, 05:03 AM
RE: Advice to buy an HP - Tugdual - 04-16-2015, 06:24 AM
RE: Advice to buy an HP - Dave Britten - 04-16-2015, 02:23 PM
RE: Advice to buy an HP - TASP - 04-16-2015, 02:29 PM
RE: Advice to buy an HP - jebem - 04-16-2015, 05:11 PM
RE: Advice to buy an HP - Gerald H - 04-16-2015, 06:01 PM
RE: Advice to buy an HP - jebem - 04-17-2015, 08:41 AM
RE: Advice to buy an HP - Cancuino - 04-16-2015, 09:54 PM
RE: Advice to buy an HP - Jlouis - 04-16-2015, 11:28 PM
RE: Advice to buy an HP - Cancuino - 04-16-2015, 11:39 PM
RE: Advice to buy an HP - MarkMason - 04-17-2015, 01:56 AM
RE: Advice to buy an HP - Marcio - 04-17-2015, 02:13 AM
RE: Advice to buy an HP - Michael Lopez - 04-17-2015, 09:42 AM
RE: Advice to buy an HP - Cancuino - 04-17-2015, 02:00 PM
RE: Advice to buy an HP - Thomas Klemm - 04-18-2015, 02:19 PM
RE: HP-80 - bshoring - 04-19-2015, 04:38 AM
RE: HP-80 - Thomas Klemm - 04-19-2015, 05:18 AM
RE: Advice to buy an HP - Cancuino - 04-19-2015, 09:11 PM
RE: Advice to buy an HP - jebem - 04-19-2015, 09:24 PM
RE: Advice to buy an HP - rprosperi - 04-19-2015, 09:25 PM
RE: Advice to buy an HP - Steve Simpkin - 04-19-2015, 09:34 PM
RE: HP-80 - bshoring - 04-19-2015 09:15 PM
RE: HP-80 - Thomas Klemm - 04-19-2015, 09:34 PM
RE: Advice to buy an HP - Cancuino - 04-19-2015, 09:37 PM
RE: Advice to buy an HP - rprosperi - 04-19-2015, 10:22 PM
RE: Advice to buy an HP - Jlouis - 04-19-2015, 11:57 PM
RE: Advice to buy an HP - Marcio - 04-20-2015, 12:16 AM
RE: Advice to buy an HP - Cancuino - 04-21-2015, 02:42 PM
RE: Advice to buy an HP - Marcio - 04-21-2015, 02:55 PM
RE: Advice to buy an HP - Thomas Ritschel - 04-21-2015, 04:34 PM
RE: Advice to buy an HP - Cancuino - 04-21-2015, 05:03 PM
RE: Advice to buy an HP - Cancuino - 04-21-2015, 04:27 PM
RE: Advice to buy an HP - Marcio - 04-21-2015, 04:35 PM
RE: Advice to buy an HP - Cancuino - 04-21-2015, 04:59 PM
RE: Advice to buy an HP - Marcio - 04-21-2015, 05:19 PM
RE: Advice to buy an HP - Tugdual - 04-21-2015, 05:26 PM
RE: Advice to buy an HP - Marcio - 04-21-2015, 05:53 PM
RE: Advice to buy an HP - Cancuino - 04-21-2015, 06:16 PM
RE: Advice to buy an HP - Marcio - 04-21-2015, 06:27 PM
RE: Advice to buy an HP - Cancuino - 04-21-2015, 05:19 PM
RE: Advice to buy an HP - Sukiari - 04-21-2015, 05:43 PM
RE: Advice to buy an HP - Cancuino - 04-21-2015, 06:13 PM
RE: Advice to buy an HP - Cancuino - 04-23-2015, 01:34 PM
RE: Advice to buy an HP - Maro - 04-23-2015, 02:02 PM
RE: Advice to buy an HP - Cancuino - 04-23-2015, 02:04 PM
RE: Advice to buy an HP - Helix - 04-23-2015, 02:16 PM
RE: Advice to buy an HP - Cancuino - 04-23-2015, 02:18 PM
RE: Advice to buy an HP - Cancuino - 04-25-2015, 03:18 PM
RE: Advice to buy an HP - Helix - 04-26-2015, 11:59 PM
RE: Advice to buy an HP - Cancuino - 04-30-2015, 09:06 AM
RE: Advice to buy an HP - rprosperi - 04-30-2015, 01:29 PM



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