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Re: Confusing Result with Series

  • To: mathgroup at smc.vnet.net
  • Subject: [mg121258] Re: Confusing Result with Series
  • From: "Dr. Wolfgang Hintze" <weh at snafu.de>
  • Date: Tue, 6 Sep 2011 03:58:18 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <j42aef$rm0$1@smc.vnet.net>

Your output is the FullForm of the expected expression.

Example on my system:
In[6]:=
Series[x/Sqrt[1 + Sqrt[x]], {x, 0, 1}]
% // FullForm

Out[6]=
x - x^(3/2) / 2 + O[x]^2
SeriesData[x, 0, List[1, Rational[-1, 2]], 2, 4, 2]

That you get the FullForm immediately is probably caused by some 
configuration setting (which I don't know, however).

Hope this helps nevertheless.

Regards,
Wolfgang

"jschwab" <jschwab at gmail.com> schrieb im Newsbeitrag 
news:j42aef$rm0$1 at smc.vnet.net...
> Hi Mathematica Gurus,
>
> I am seeing confusing behavior with the Series command, using
> Mathematica 7.0.1 on Mac OS X.
> Specifically, it is not always truncating at the order I would 
> expect.
> Here's a a simple example of the problem I'm having.
>
> I expect that the result of a a series expansion of
> \frac{x}{\sqrt{1 + \sqrt{x}}}
> to first order will be
> x + O(x^{3/2})
> no matter how I write the input.
>
> Instead, I see the following behavior.
>
> In[175]:= Series[x/Sqrt[1 + Sqrt[x]], {x, 0, 1}]
> Out[175]= SeriesData[x, 0, {1, Rational[-1, 2]}, 2, 4, 2]
>
> In[176]:= Series[Sqrt[x^2/(1 + Sqrt[x])], {x, 0, 1}]
> Out[176]= SeriesData[x, 0, {1}, 2, 3, 2]
>
> Is this a known issue? Or some sort of expected behavior that I
> haven't understood?
> A naive Google search didn't reveal anything of particular relevance.
>
> Thanks,
> Josiah
> 





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