For which models was 2^3>8?

04042017, 07:18 PM
(This post was last modified: 04042017 07:19 PM by Dieter.)
Post: #11




RE: For which models was 2^3>8?
(04042017 06:45 PM)james summers Wrote: Thanks for the great explanation, Dieter. Interesting. Without guard digits it should be 7.9999973. What are the intermediate results you get for ln 2 and 3x this? (04042017 06:45 PM)james summers Wrote: The 25C is more accurate, but similar, in that [2] [ENTER] [3] [y^{x}] and [2] [ENTER] [ln] [3] [x] [e^{x}] both give 8,000000002. The 25 uses 10 digits as opposed to 8 in the MK61. (04042017 06:45 PM)james summers Wrote: However, my 32E, 41CV and 15C, whilst giving [2] [ENTER] [3] [y^{x}] as 8.000000000, for [2] [ENTER] [ln] [3] [x] [e^{x}] they give 8,000000003. Why do you add an [ENTER] before the log? It's classic RPN. ;) The HP32/41/15 of course use the "new accuracy" since 1976 with three additional guard digits. That's why even with a manually calculated exponentional you get the correctly rounded value ...003. The difference to the HP25 result ...002 is probably due to different algorithms and/or rounding methods. In 1976 there were more improvements than just adding the guard digits, cf. the mentioned HP Journal article. BTW, if you do not have access to the latter: most of the interesting stuff is available on hpl.hp.com. Dieter 

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