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Re: Is there a simple way to transform 1.1 to 11/10?

• To: mathgroup at smc.vnet.net
• Subject: [mg93006] Re: Is there a simple way to transform 1.1 to 11/10?
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Wed, 22 Oct 2008 05:41:17 -0400 (EDT)
• Organization: Uni Leipzig
• References: <gdkajv$4r2$1@smc.vnet.net>
• Reply-to: kuska at informatik.uni-leipzig.de

Hi,

yes, you need a new computer, that does not use
the binary system, because 1.000000001 can't repesented
as exact number in the binary system (it has an
infinite periodic representation, that must be truncated).
When I remember right, on of the first Russian computers
(approx. 1950) worked with base 3. May be you found one in a
museum.

Regards
   Jens



Alain Cochard wrote:
> The obvious
> 
>     In[1]:= x=1.1`Infinity
> 
> is not syntactically correct.
> 
> I understand that SetPrecision[1.1,Infinity] does not work either:
> 
>     In[3]:= SetPrecision[1.1,Infinity]
> 
>             2476979795053773
>     Out[3]= ----------------
>             2251799813685248
> 
>     In[4]:= N[%,20]
> 
>     Out[4]= 1.1000000000000000888
> 
> I searched the newsgroup and thought I had the solution with Rationalize:
> 
>     In[5]:= Rationalize[1.1,0]
> 
>             11
>     Out[5]= --
>             10
> 
> But
> 
>     In[9]:= Rationalize[1.000000001,0]
> 
>             999999918
>     Out[9]= ---------
>             999999917
> 
>     In[10]:= N[%,20]
> 
>     Out[10]= 1.0000000010000000830
> 
> So any simple way?
> 
> Thanks,
> Alain
> 

• Follow-Ups:
  • Re: Re: Is there a simple way to transform 1.1 to 11/10?
    • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>
  • Good computer needed
    • From: Artur <grafix@csl.pl>