HP-71B Enhanced Math LEX
01-26-2020, 03:08 PM (This post was last modified: 01-26-2020 07:58 PM by Albert Chan.)
Post: #14
 Albert Chan Senior Member Posts: 2,230 Joined: Jul 2018
RE: HP-71B Enhanced Math LEX
(01-26-2020 10:54 AM)J-F Garnier Wrote:  The weakness of the z^2 operation in the HP71 Math ROM was mentioned in this article (last pages) of W. Kahan, now it is fixed!

Thanks for the update !

Replacing Z^2 as Z*Z almost always give better result.
It take a while to find a counter-example.

>X=.254661579433 @ Y=.260740997689
>COMPLEX Z @ Z = (X,Y)
>Z^2
(-3.13334783654, .132801428589)
>Z*Z
(-3.13334783655, .132801428589)

Real part of Z = X*X - Y*Y = (X+Y) * (X-Y) gives better result.
> (X+Y) * (X-Y) ﻿ ﻿ ﻿ ﻿ ﻿ ﻿ ﻿ ﻿ ! exact value = -3.13334783654 4934739232
-3.13334783654
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 Messages In This Thread HP-71B Enhanced Math LEX - J-F Garnier - 01-09-2020, 07:30 PM RE: HP-71B Enhanced Math LEX - rprosperi - 01-09-2020, 10:36 PM RE: HP-71B Enhanced Math LEX - Valentin Albillo - 01-10-2020, 12:00 AM RE: HP-71B Enhanced Math LEX - charger73 - 01-10-2020, 07:23 AM RE: HP-71B Enhanced Math LEX - Raymond Del Tondo - 01-10-2020, 08:58 AM RE: HP-71B Enhanced Math LEX - Sylvain Cote - 01-10-2020, 04:16 PM RE: HP-71B Enhanced Math LEX - Albert Chan - 01-10-2020, 04:44 PM RE: HP-71B Enhanced Math LEX - Albert Chan - 01-10-2020, 05:01 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 01-10-2020, 05:40 PM RE: HP-71B Enhanced Math LEX - Albert Chan - 01-10-2020, 06:29 PM RE: HP-71B Enhanced Math LEX - Erwin - 01-13-2020, 06:10 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 01-13-2020, 07:13 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 01-26-2020, 10:54 AM RE: HP-71B Enhanced Math LEX - Albert Chan - 01-26-2020 03:08 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 01-27-2020, 08:05 AM RE: HP-71B Enhanced Math LEX - Albert Chan - 01-27-2020, 11:35 AM RE: HP-71B Enhanced Math LEX - J-F Garnier - 01-27-2020, 12:42 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 02-12-2020, 07:55 AM RE: HP-71B Enhanced Math LEX - rprosperi - 02-12-2020, 01:55 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 02-14-2020, 12:23 PM RE: HP-71B Enhanced Math LEX - rprosperi - 02-14-2020, 03:04 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 03-19-2020, 07:30 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 04-27-2020, 09:42 AM RE: HP-71B Enhanced Math LEX - Erwin - 04-27-2020, 04:50 PM RE: HP-71B Enhanced Math LEX - Albert Chan - 03-17-2021, 09:00 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 03-18-2021, 08:22 AM RE: HP-71B Enhanced Math LEX - J-F Garnier - 08-08-2020, 09:37 AM RE: HP-71B Enhanced Math LEX - Valentin Albillo - 08-08-2020, 10:14 PM RE: HP-71B Enhanced Math LEX - Paul Dale - 08-09-2020, 11:15 AM RE: HP-71B Enhanced Math LEX - John Keith - 08-09-2020, 02:16 PM RE: HP-71B Enhanced Math LEX - Valentin Albillo - 08-09-2020, 03:49 PM RE: HP-71B Enhanced Math LEX - Erwin - 08-10-2020, 08:21 PM RE: HP-71B Enhanced Math LEX - rprosperi - 08-10-2020, 09:42 PM RE: HP-71B Enhanced Math LEX - Erwin - 08-11-2020, 02:47 PM RE: HP-71B Enhanced Math LEX - Dave Frederickson - 08-11-2020, 04:24 PM RE: HP-71B Enhanced Math LEX - Erwin - 08-11-2020, 05:06 PM RE: HP-71B Enhanced Math LEX - Gene - 08-09-2020, 01:49 AM RE: HP-71B Enhanced Math LEX - Paul Dale - 08-09-2020, 10:10 AM RE: HP-71B Enhanced Math LEX - John Keith - 08-09-2020, 01:04 PM RE: HP-71B Enhanced Math LEX - Dave Frederickson - 08-11-2020, 05:17 PM RE: HP-71B Enhanced Math LEX - Erwin - 08-13-2020, 07:35 AM RE: HP-71B Enhanced Math LEX - Dave Frederickson - 08-13-2020, 03:27 PM RE: HP-71B Enhanced Math LEX - Erwin - 08-13-2020, 04:00 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 08-14-2020, 07:53 AM RE: HP-71B Enhanced Math LEX - Dave Frederickson - 08-14-2020, 09:06 PM RE: HP-71B Enhanced Math LEX - Erwin - 08-20-2020, 08:11 PM RE: HP-71B Enhanced Math LEX - Dave Frederickson - 08-20-2020, 08:34 PM RE: HP-71B Enhanced Math LEX - Erwin - 08-21-2020, 05:34 PM RE: HP-71B Enhanced Math LEX - J-F Garnier - 09-27-2020, 06:25 PM RE: HP-71B Enhanced Math LEX - Dave Frederickson - 09-27-2020, 06:52 PM

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