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Re: Problem with Precision?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg34479] Re: Problem with Precision?
  • From: "Allan Hayes" <hay at haystack.demon.co.uk>
  • Date: Thu, 23 May 2002 03:32:21 -0400 (EDT)
  • References: <acff17$rpn$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Mike,

The output from entering 1.602176462 is just this number.
This is shown by

    InputForm[1.602176462]

        1.602176462

So the precision is there to calculate with.

Only six significant digits are displayed because the default setting of the
option PrintPrecision is PrintPrecision -> 6

    1.602176462

        1.60218

To arrange that inexact numbers in all your notebooks are displayed with up
to 10 of the significat digits we need to change the setting to
PrintPrecision->10:
 - menu>Format>Option Inspector
 - in the Show option values for field choose global
 - look up Print, find the option,  set its value to 10 and click Apply at
the top right of the panel

    1.602176462

        1.602176462

 - (notice that a ball appears to the left of the option to indicate an
altered value - the default value can be restored by  double clicking this
ball)

 The setting can be restricted to a selection or a notebook by choosing
selection or notebook in place of global.

 Of course, if we only enter, for example, 6 significant digits then only
six will be displayed

    12.3456

        12.3456

--
Allan

---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
www.haystack.demon.co.uk
hay at haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565


>
> Can anyone shed any light on why
>
> N[1.602176462,10]
>
> gives
>
> 1.60218
>
> I need it to be as accurate as I can get it and 5 dp doesn't cut it.  Any
> ideas?
>
> Thanks
>
> Mike
>
>
>




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