Re: Sigma function in equation editors Message #16 Posted by Karl Schneider on 4 Mar 2009, 3:05 a.m., in response to message #1 by Don Shepherd
Hi, Don --
Quote:
Since many formulae require the summation, or sigma, function, I was wondering why it was not included in the 33s and 35s.
The crux of the matter is that the HP-33s/35s equation editor is fundamentally the one ported from the algebraic HP-22S into the RPN HP-32SII in 1991 and subsequently carried forward; it is not the more-advanced implementation of the HP-17B/27S.
The Sigma operator for the HP-17B/27S equation editor will, by looping, compute finite series using an expression that defines every term. (Sigma+, by contrast, only adds a single datum to a summation.) The HP-17B/27S does not use summation for statistics, so there is no Sigma+ function.
The HP-22S equation editor allowed only programmable calculating operations -- or most of them -- defined on its keyboard. Sigma+ is one that was not supported, because it is not very practical for an equation. Sigma as a construct used in equations, however, might have caused confusion with Sigma+.
-- KS
Edited: 4 Mar 2009, 3:19 a.m.
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