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Re: Question about precision.

  • To: mathgroup at smc.vnet.net
  • Subject: [mg38442] Re: Question about precision.
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Mon, 16 Dec 2002 02:20:19 -0500 (EST)
  • Organization: Universitaet Leipzig
  • References: <atcasb$3m0$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

you have alread, Mathematica only Print[] the short form

Sqrt[1.3] // FullForm

You can still use

Sqrt[1.3`1000000]

if you need more digits.

Regards
  Jens

Wen-Feng Hsiao wrote:
> 
> Dear experts,
> 
> I try to find the square root of 1.3, but obtain an not so correct
> answer. Could someone point me how to do? My trials are the
> followings.
> 
> In[28]:=
> Sqrt[1.3]
> 
> Out[28]=
> 1.14018
> 
> In[29]:=
> Precision[Sqrt[1.3]]
> 
> Out[29]=
> 16
> 
> In[30]:=
> N[Sqrt[1.3], 50]
> 
> Out[30]=
> 1.14018
> 
> In[31]:=
> 1.14018*1.14018
> 
> Out[31]=
> 1.30001
> 
> The more precise answer should be
> In[32]:=
> 1.140175425*1.140175425
> 
> Out[32]=
> 1.3
> 
> Thanks for your help!
> 
> Wen-Feng Hsiao


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