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. >