RE: Re: Precision of output

*To*: mathgroup at smc.vnet.net*Subject*: [mg48240] RE: [mg48222] Re: Precision of output*From*: "DrBob" <drbob at bigfoot.com>*Date*: Wed, 19 May 2004 02:42:18 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

N[expr,n] determines the way expr is evaluated, not how the result is SHOWN. NumberForm controls display. DrBob www.eclecticdreams.net -----Original Message----- From: Bill Rowe [mailto:readnewsciv at earthlink.net] To: mathgroup at smc.vnet.net Subject: [mg48240] [mg48222] Re: Precision of output On 5/17/04 at 3:22 AM, spam at husumtoften.invalid (Per RÂ¯nne) wrote: >If I write: > >N[4209/0.14,100] I get: 30064.3 >But if I write N[420900/14,100] I get: >30064. >285714285714285714285714285714285714285714285714285714285714285714 >285714\ 28571428571428571428571 >Why the difference? I thought N determined the number of digitals >shown - but I seem to have some problems with this function. And it >is not in this example only. The difference is caused by using an exact number in one case and an inexact number in the other case. In particular the documentation states: Unless numbers in expr are exact, or of sufficiently high precision, N[expr, n] may not be able to give results with n digit precision. When you write 0.14 you are expressing a number with much less precision than 100 digits. Consequently, there is no valid way to get 100 digit precision from 4209/.014 -- To reply via email subtract one hundred and four