Re: Incorrect Summation
- To: mathgroup at smc.vnet.net
- Subject: [mg129200] Re: Incorrect Summation
- From: amzoti <amzoti at gmail.com>
- Date: Thu, 20 Dec 2012 03:27:31 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- Delivered-to: l-mathgroup@wolfram.com
- Delivered-to: mathgroup-newout@smc.vnet.net
- Delivered-to: mathgroup-newsend@smc.vnet.net
- References: <20121218073534.C7529694B@smc.vnet.net> <kas30a$ciq$1@smc.vnet.net>
On Wednesday, December 19, 2012 1:56:26 AM UTC-8, Murray Eisenberg wrote:
> What did you type, exactly, for Wolfram|Alpha? I tried several "obvious" things, e.g.,
>
> sum cos(log(log(k)))/log(k) for k from 2 to infinity
>
> but WA was unable even to interpret it correct as asking for the sum of an infinite series.
>
> On Dec 18, 2012, at 2:35 AM, amzoti <amzoti at gmail.com> wrote:
>
> > Hi All,
>
> > can someone try this and see if it returns an incorrect result?
>
> > Sum[Cos[Log[Log[k]]]/Log[k],{k,2,Infinity}]
>
> > I tried it on WA and believe the result is incorrect.
>
> > Thanks.
> ---
>
> Murray Eisenberg murray at math.umass.edu
>
> Mathematics & Statistics Dept.
>
> Lederle Graduate Research Tower phone 413 549-1020 (H)
>
> University of Massachusetts 413 545-2838 (W)
>
> 710 North Pleasant Street fax 413 545-1801
>
> Amherst, MA 01003-9305
Just copy and paste the expression as-is:
Sum[Cos[Log[Log[k]]]/Log[k],{k,2,Infinity}]
For this example, if you increase the number of points to max on WA, you can see where I think the result is going astray and why this is returning an incorrect result.
Aside:
It is odd that sometimes WA accepts the user inputs in standard notation, but other times, it seems to get confused.
I would think that if a user knows how to type Mathematica standard syntax correctly, that WA should be able to accept it.
Thanks -A
- References:
- Incorrect Summation
- From: amzoti <amzoti@gmail.com>
- Incorrect Summation