HP 50g - summation
06-03-2016, 05:20 PM (This post was last modified: 06-03-2016 05:25 PM by Claudio L..)
Post: #4
 Claudio L. Senior Member Posts: 1,840 Joined: Dec 2013
RE: HP 50g - summation
(06-03-2016 12:47 PM)Simone Cerica Wrote:  Hello everyone, is there a way to make a summation in such a way that

'\GS(N=1,5,XN)' = 'X1+X2+X3+X4+X5' ?

Simone

Code:
 << -> N V  << 1 N FOR K  'V' RCL  ->STR TAIL HEAD K + STR-> NEXT WHILE N 1 > REPEAT + 'N' DECR DROP END >> >>

Store it in let's say XSUM, then:
'XSUM(5,X)' EVAL will produce what you want. It's limited to single-letter identifiers (by using TAIL HEAD, this can be improved).
Another improvement could be a start value for N, but you get the idea.

Quick footnote: For those trying this in newRPL, the TAIL HEAD combination needs to be removed, as the identifiers in symbolics are unquoted, then the code is good for arbitrary length identifiers.
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 Messages In This Thread HP 50g - summation - Simone Cerica - 06-03-2016, 12:47 PM RE: HP 50g - summation - wojtek - 06-03-2016, 03:36 PM RE: HP 50g - summation - Tugdual - 06-03-2016, 04:21 PM RE: HP 50g - summation - Claudio L. - 06-03-2016 05:20 PM RE: HP 50g - summation - Simone Cerica - 06-04-2016, 09:26 AM

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