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Re: Why?

• To: mathgroup at smc.vnet.net
• Subject: [mg110006] Re: Why?
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Fri, 28 May 2010 07:22:58 -0400 (EDT)

Precision[1.000000000000000000000001]

24.

If you want precision to 60 digits then all numbers used must be at least that precise.

N[1000000000000000000000001*^-24 - 1, 60]

1.00000000000000000000000000000000000000000000000000000000000*10^-24

Precision[%]

60.

1.000000000000000000000001`60 - 1

1.00000000000000000000000000000000000*10^-24

Precision[%]

36.


Bob Hanlon

---- Alexey <lehin.p at gmail.com> wrote: 

=============
Hello,
Consider the following:

In[1]:= N[1.000000000000000000000001 - 1, 60]

Out[1]= 0.*10^-24

I can not understand why this happens. Can anyone explain the reason?
What is about "arbitrary precision arithmetics"?