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MathGroup Archive 2007

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Re: A Series test

  • To: mathgroup at smc.vnet.net
  • Subject: [mg72784] Re: A Series test
  • From: "Scout" <sarner2006-sem at yahoo.it>
  • Date: Fri, 19 Jan 2007 02:05:37 -0500 (EST)
  • Organization: [Infostrada]
  • References: <eonhr6$i8$1@smc.vnet.net>

If you want to try another way to solve your problem,
instead of ComplexExpand[], FullSimplify[], etc.
you could download the AbsArg package from here:
http://library.wolfram.com/infocenter/MathSource/4485/#downloads
This package also needs the file "NonNegativeQ.m"
     http://library.wolfram.com/infocenter/MathSource/647/

HTH,
    ~Scout~

<carlos at colorado.edu>  wrote
news:eonhr6$i8$1 at smc.vnet.net...
> Just curious. Could somebody pls run this script on the
> latest Mathematica user version (I think it's 5.2) under
> Windows or Unix  and report the results:
>
> rho=(x+a*I)/(x-a*I); R=Abs[rho];
> s=Series[R,{x,0,4}];
> Print[FullSimplify[s,a>=0&&x>=0]//InputForm];
>
> My 5.0 answer (Mac G5 under OS 10.4.8) is
>
> SeriesData[x, 0, {1, (-2*I)/a, (-2*(1 + Derivative[2][Abs][-1]))/a^2,
> (((2*I)/3)*(3 + 6*Derivative[2][Abs][-1] - 2*Derivative[3][Abs][-1]))/
>    a^3, (2*(3 + 9*Derivative[2][Abs][-1] - 6*Derivative[3][Abs][-1] +
> Derivative[4][Abs][-1]))/(3*a^4)}, 0, 5, 1]
>
> The correct answer is 1. (The result with Simplify is more
> complicated.)  Thanks.
>



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