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From: Ben on 16 Sep 2006 22:51 Anyone know what causes this message? I get when trying to find the limit as n approaches infinity of sigma from 1 to n of one over x plus x.
From: TE on 17 Sep 2006 05:56 Ben wrote: > Anyone know what causes this message? > I get when trying to find the limit as n approaches infinity of sigma > from 1 to n of one over x plus x. with sigma if you mean the summation than have a look at "advanced user's reference manual" for the hp49g+/hp48gII at page3-212: \GS (Summation) Type: Function Description: Summation Function: Calculates the value of a finite series. it will not help, but maybe it informs a bit. tom
From: Steen Schmidt on 17 Sep 2006 07:26 Ben wrote: > Anyone know what causes this message? > I get when trying to find the limit as n approaches infinity of sigma > from 1 to n of one over x plus x. Please state mathematical expressions algebraically instead of in text - it makes it much easier to understand (and to not misunderstand). As I understand it (after reading your question a dozen times) you are trying to evaluate 'lim(SIGMA(X=1,n,1/X+X),n=inf)'? If you did it step-by-step (first evaluate the sum, then take the limit), you'd probably have an idea of which step went wrong. In this case the summation goes fine but the limit function chokes on the result. Which operators could lim choke on? Since only +, -, *, /, ^ and Psi are represented, I'd venture a guess and say that the operator that is not implemented in the SERIES function (which is apparantly used by lim) is Psi. Another one not implemented is ! (the factorial operator). Regards Steen
From: acl on 18 Sep 2006 10:14 Ben wrote: > Anyone know what causes this message? > I get when trying to find the limit as n approaches infinity of sigma > from 1 to n of one over x plus x. > Hi Ben, Out of curiosity, what do you expect this limit to be? Cheers.
From: Chris Smith on 18 Sep 2006 11:06
acl <achilleaslazarides (a)yahoo.co.uk> wrote:> Hi Ben, > Out of curiosity, what do you expect this limit to be? > Cheers. Good question. The ratio test is indeterminate (the limit is one), but the series doesn't appear to be converging to anything as n gets up to the 1 million range. I'd guess the correct answer is +inf. I am not great at this stuff, but I don't see a way to establish that as fact, rather than supposition. (I'm not Ben; just jumping in.) -- Chris Smith |