HP Forum Archive 14

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hp49g+ bug? Combinations, sums, and equivalence Message #1 Posted by Eddie Shore on 15 Mar 2005, 1:07 a.m. The following is true: COMB(n, 2) + n = Sum of all integers from 1 to n i.e. if n = 5 COMB(5, 2) + 5 = 5! ÷ (3!*2!) + 5 = 10 + 5 = 15 and 1 + 2 + 3 + 4 + 5 = 15 However, when I input 'COMB(5,2) + 5' on one level, and '[Capital Sigma symbol](X=1,5,X)' on the other, and I execute the == command on the Program-Test Menu, I get a 0 as a result (incorrect result) Both objects inputed are same type (9 - algebriac expressions?). A bug in the 49g+ CAS perhaps.

Re: hp49g+ bug? Combinations, sums, and equivalence Message #2 Posted by Arnaud Amiel on 15 Mar 2005, 2:00 a.m., in response to message #1 by Eddie Shore Strange: In the stack I can't recreate your bug: I do: Experssion 1 [ENTER] Expression 2 [ENTER] == [EVAL] I get 1. If I put the same in a program, I get 0. Arnaud

Re: hp49g+ bug? Combinations, sums, and equivalence Message #3 Posted by Raymond Del Tondo on 15 Mar 2005, 2:07 a.m., in response to message #1 by Eddie Shore Hi, the 0 doesn't mean 'incorrect result'. The result is correct, the expressions are simply not the same, as you can easily see on the stack. Maybe it also depends on the status of the evaluation flags, this may be a case for RTFM;-) Raymond

What's RTFM? :) Message #4 Posted by Eddie Shore on 15 Mar 2005, 9:41 a.m., in response to message #3 by Raymond Del Tondo *NM*

Re: What's RTFM? :) Message #5 Posted by Raymond Del Tondo on 15 Mar 2005, 10:07 a.m., in response to message #4 by Eddie Shore RTFM ~ Read The 'Fascinating' Manual...;-) As VPN pointed out, the result seems to depend on either the mode, and/or the type of arguments. Raymond

Re: What's RTFM? :) Message #6 Posted by bill platt on 16 Mar 2005, 10:56 a.m., in response to message #5 by Raymond Del Tondo Which is actually taken as a friendly reminder or suggesttion among friends. It only shows irritation when you get to, "RTFM-41" which means, "read the "funny" manual for once!" Another version is RTFD41 for which "D" stands for "drawing" as in mechanical drawing. regards, Bill

Re: hp49g+ bug? Combinations, sums, and equivalence Message #7 Posted by Veli-Pekka Nousiainen on 15 Mar 2005, 7:56 a.m., in response to message #1 by Eddie Shore Seems to be one of the "features of the calc Using Approx ~ mode or reals (5.) will give the correct answer. [VPN]

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