Re: About squaring a number on my HP... Message #31 Posted by Thomas Okken on 9 Dec 2010, 10:06 p.m., in response to message #29 by Gerson W. Barbosa
Quote: Free42 Decimal, for instance, returns 5.062499999999999999999412 internally
Hi Gerson!
This is a bit OT -- but which release of Free42 are you using?
AFAIK all 1.4.66 versions get 2.25^2 exactly right, regardless of whether you use Decimal or Binary, and regardless of whether you calculate 2.25^2 using ENTER *, X^2, Y^X, LN 2 * E^X, or LOG 2 * 10^X.
What you describe, an error of almost 600 ULP for a simple calculation involving transcendentals, should not happen with any Decimal version >= 1.4.52, and with no Binary version since 1.0.
(The < 1.4.52 Decimal versions evaluated transcendentals to less than full accuracy, guaranteeing at least 20 digits accuracy but not the full 25 digits that all other functions produce... But since 1.4.52 they use one or two additional terms in the Taylor series, and should be accurate to 1 ULP now.)
- Thomas
Edited: 9 Dec 2010, 10:31 p.m.
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