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Topic: I do not understand result from wolfram
Replies: 3   Last Post: May 7, 2013 9:27 AM

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JT

Posts: 1,150
Registered: 4/7/12
Re: I do not understand result from wolfram
Posted: May 7, 2013 12:02 AM
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On 6 Maj, 19:46, JT <jonas.thornv...@gmail.com> wrote:
> On 6 Maj, 19:33, JT <jonas.thornv...@gmail.com> wrote:
>
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> > On 6 Maj, 11:50, Dan <dan.ms.ch...@gmail.com> wrote:
>
> > > On May 6, 2:57 am, JT <jonas.thornv...@gmail.com> wrote:
>
> > > > Compare this onehttp://www.wolframalpha.com/input/?i=0.49999999%3D%28%28n%2F2%29-1%29...
> > > > n = 1.x10^8

>
> > > > and this onehttp://www.wolframalpha.com/input/?i=0.499999999999999999999999999999...
>
> > > > n=-1?
>
> > > > Is there something wrong with wolfram alpha, or can it not handle big
> > > > numb libraries?

>
> > > k =  (n/2 - 1) / n =>
> > > n k = (n/2 - 1)    =>
> > > n( 1/2  - k)  = 1 =>

>
> > > n = 1 / (0.5  - k)
>
> > > k = 0.49 => 0.5 - 0.49 = 0.01 => n = 1/ 0.01 = 100
> > > k = 0.4999 => 0.5 - 0.4999 = 0.0001 => n = 1/ 0.0001 = 10000

>
> > > Both wolfram results are correct .Small variations in a parameter can
> > > produce huge variations in the result, if you're on the other side of
> > > the fraction :

>
> > >http://library.thinkquest.org/2647/media/odd1ox.gif
>
> > > For the record, I think you meant to input 0.4999  = - (n/2  + 1) / n
> > > This has solution n = -1 as the parameter goes to 0.5

>
> > > 0.4999  = (n/2  - 1) / n
> > > has an indefinite solution of n going to +/- infinity as the parameter
> > > goes to 0.5

>
> > I am not sure i understand how -1 could be correct, if n is the number
> > of sides of a polygon (n/2-1)/n*360 is inner angle of a uniform
> > polygon in degrees, and (n/2-1)/n is in revolutions.
> > The series will of course converge into a straight line at 0.5
> > revolutions when reaching infinity as you noted, but for any natural n
> > the series should just come closer to 0.5 .

>
> > 0.49=(100/2-1)/100
> > 0.499=(1000/2-1)/1000
> > 0.4999=(10000/2-1)/10000
> > 0.49999=(100000/2-1)/100000
> > 0.499999=(1000000/2-1)/1000000
> > 0.4999999=(10000000/2-1)/10000000

>
> > Are you saying there is a max number number of sides of a polygon?
>
> Or are you saying that (n/2-1)360 is not correct formula for sum of
> angles of any uniform polygon?
> I feel a bit lost here.


Isn't (n/2-1)the sum of angles in turns of a polygon of n sides/
vertices?



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