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Re: Bug in calculating -3^49999.0

• To: mathgroup at smc.vnet.net
• Subject: [mg66014] Re: [mg65989] Bug in calculating -3^49999.0
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Thu, 27 Apr 2006 02:25:56 -0400 (EDT)
• References: <200604260837.EAA02684@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

x=(-3)^49999.;

x/.z_Complex:>Re[z]*Chop[1+I*Im[z]/Re[z]]

-3.8513654349963041533518106689182`15.954589770191*^23855

x/. z_Complex:>Abs[z]*Chop[x/Abs[z]]

-3.85136543499630415335181066893086`15.47746851547134*^23855


Bob Hanlon
hanlonr at cox.net



On Apr 26, 2006, at 4:37 AM, kowald at molgen.mpg.de wrote:

> Hello everybody,
>
> I'm using Mathematica 5.1 under Win2k and I found a bug when I try  
> to compute
> -3^49999. I get:
>
> -3^49999 //N  =>  -3.85 * 10^23855          okay
> -3^49999.      =>  -3.85 * 10^23855          okay
> (-3)^49999.    =>  -3.85 * 10^23855 + 4.56*10^23844 i       wrong
> (-3)^49999     =>  -3.85 * 10^23855          okay
>
> Is this a known problem?
> Is there a work around ?
> Obviously this is part of a more complicated calculation and so I
> cannot simply leave out the brackets.
>
>  Many thanks,
>
>                 Axel
>

• References:
  • Bug in calculating -3^49999.0
    • From: kowald@molgen.mpg.de