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MathGroup Archive 2005

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Re: Re: odd mathematica blindspot

  • To: mathgroup at smc.vnet.net
  • Subject: [mg56548] Re: [mg56502] Re: odd mathematica blindspot
  • From: Edward Peschko <esp5 at pge.com>
  • Date: Thu, 28 Apr 2005 02:40:51 -0400 (EDT)
  • References: <d4klbs$eg7$1@smc.vnet.net> <200504270153.VAA01785@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

From: Edward Peschko <esp5 at pge.com>
To: mathgroup at smc.vnet.net
Bcc: 
Subject: [mg56548] Re: [mg56502] Re: odd mathematica blindspot
Reply-To: 

On Tue, Apr 26, 2005 at 09:53:49PM -0400, Skirmantas wrote:
> Hi Ed,
> 
> By definition, 9999999999999/10000000000000 is an exact rational number, whereas 0.5 is an approximate real number:

Well, that's completely unintuitive..  I understand it, but it still rubs me the 
wrong way for some reason. '.5' on paper means that to me - .5 - not .4999999999
or .50000000001 or whatever internal representation the computer chooses.. In fact, 
that's why I got Mathematica in the first place, to get away from this approximate
stuff.

Why couldn't mathematica treat .5 as a string, make the internal calculation 
and turn .5 into 5/10? Or, barring that, is there a conversion function for this 
(going back and forth between rational and approximate real?

Ed


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