Calculating e^x-1 on classic HPs
01-14-2016, 06:50 PM (This post was last modified: 01-14-2016 06:53 PM by Gerson W. Barbosa.)
Post: #19
 Gerson W. Barbosa Senior Member Posts: 1,362 Joined: Dec 2013
RE: Calculating e^x-1 on classic HPs
(01-13-2016 06:43 PM)Dieter Wrote:  Accuracy problems have also been addressed in the mentioned 2014 thread. That's why back then I suggested another ln(1+x) method using sinh.

On the other hand a dedicated ex–1 function is only required for ln 0,9 < x < ln 2, and here your method works fine. One might add two additional tests to check whether the argument is within these bounds or not. Which again makes the method less elegant...

Here is my plan B for the hyperbolic function approach:

Code:
 001- LBL B 002- e^x 003- LSTx 004- 2 005- / 006- HYP TAN 007- * 008- LSTx 009- + 010- RTN

No additional tests required. On the HP-15C I get the same results of the HP-12C running your program, except for occasional differences of one digit in the last significant digit.
I won't post the formula here because it's very difficult to edit it in this tiny 4" screen, but it's apparent from the listing. Windows 10 refuses to start on my desktop computer. I guess the "CPU Over Voltage Error!" I've been receiving when attempting to boot has something to do with that...

Gerson
 « Next Oldest | Next Newest »

 Messages In This Thread Calculating e^x-1 on classic HPs - Dieter - 01-11-2016, 10:20 PM RE: Calculating e^x-1 on classic HPs - Thomas Klemm - 01-12-2016, 01:41 AM RE: Calculating e^x-1 on classic HPs - Dieter - 01-12-2016, 06:12 PM RE: Calculating e^x-1 on classic HPs - Claudio L. - 01-12-2016, 05:13 AM RE: Calculating e^x-1 on classic HPs - Dieter - 01-12-2016, 02:02 PM RE: Calculating e^x-1 on classic HPs - ElectroDuende - 01-12-2016, 03:34 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-12-2016, 06:30 PM RE: Calculating e^x-1 on classic HPs - Claudio L. - 01-12-2016, 09:44 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-12-2016, 08:16 PM RE: Calculating e^x-1 on classic HPs - Gerson W. Barbosa - 01-13-2016, 03:46 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-13-2016, 06:43 PM RE: Calculating e^x-1 on classic HPs - Gerson W. Barbosa - 01-14-2016, 02:47 AM RE: Calculating e^x-1 on classic HPs - Dieter - 01-14-2016, 01:44 PM RE: Calculating e^x-1 on classic HPs - Gerson W. Barbosa - 01-14-2016, 03:30 PM RE: Calculating e^x-1 on classic HPs - Gerson W. Barbosa - 01-14-2016 06:50 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-14-2016, 07:38 PM RE: Calculating e^x-1 on classic HPs - Gerson W. Barbosa - 01-14-2016, 07:50 PM RE: Calculating e^x-1 on classic HPs - Albert Chan - 02-02-2019, 07:32 PM RE: Calculating e^x-1 on classic HPs - Dieter - 02-03-2019, 06:46 PM RE: Calculating e^x-1 on classic HPs - Paul Dale - 01-14-2016, 07:20 AM RE: Calculating e^x-1 on classic HPs - Dieter - 01-14-2016, 01:48 PM RE: Calculating e^x-1 on classic HPs - emece67 - 01-14-2016, 03:55 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-14-2016, 06:42 PM RE: Calculating e^x-1 on classic HPs - emece67 - 01-14-2016, 09:14 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-14-2016, 09:55 PM RE: Calculating e^x-1 on classic HPs - Paul Dale - 01-15-2016, 01:19 AM RE: Calculating e^x-1 on classic HPs - Dieter - 01-15-2016, 02:00 PM RE: Calculating e^x-1 on classic HPs - matthiaspaul - 01-15-2016, 10:10 AM RE: Calculating e^x-1 on classic HPs - Gerson W. Barbosa - 01-15-2016, 06:07 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-15-2016, 06:46 PM RE: Calculating e^x-1 on classic HPs - Gerson W. Barbosa - 01-15-2016, 10:45 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-16-2016, 08:19 AM RE: Calculating e^x-1 on classic HPs - Gerson W. Barbosa - 01-16-2016, 12:40 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-16-2016, 01:32 PM RE: Calculating e^x-1 on classic HPs - Albert Chan - 02-02-2019, 07:22 PM RE: Calculating e^x-1 on classic HPs - Paul Dale - 01-14-2016, 09:22 PM RE: Calculating e^x-1 on classic HPs - Dieter - 01-14-2016, 09:49 PM RE: Calculating e^x-1 on classic HPs - Paul Dale - 01-15-2016, 01:15 AM RE: Calculating e^x-1 on classic HPs - Albert Chan - 02-03-2019, 08:28 PM RE: Calculating e^x-1 on classic HPs - Albert Chan - 02-04-2019, 07:28 PM RE: Calculating e^x-1 on classic HPs - Dieter - 02-04-2019, 07:59 PM

User(s) browsing this thread: 1 Guest(s)