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Re: Precision of output

• To: mathgroup at smc.vnet.net
• Subject: [mg48236] Re: Precision of output
• From: spam at husumtoften.invalid (Per Rønne)
• Date: Wed, 19 May 2004 02:42:12 -0400 (EDT)
• References: <c89q2f$t51$1@smc.vnet.net> <c8chjk$epj$1@smc.vnet.net>
• Reply-to: spam at husumtoften.dk (Per Rønne)
• Sender: owner-wri-mathgroup at wolfram.com

Kazimir <kazimir04 at yahoo.co.uk> wrote:

> Mathematica thinks that only the first two digits are precise and
> knows nothing about the consecutive digits. In other words it's a
> standor notation for any number between 0.13500000(continue) and
> 0.1449999999(continue). Thus, it can not suppose that it will find a
> preciser answer. To get the desired answer you have to ask
> N[4209/SetPrecision[0.14, &#8734;], 100]
> or 
> 4209/(0.14``100)
> In the latest case you say that 0.14 is defined with 100 digits and it
> finds the result with this precision
> 
> 
> > But if I write N[420900/14,100] I get:
> > 30064.285714285714285714285714285714285714285714285714285714285714285714
> > 285714\
> > 28571428571428571428571
> Here, you don't put a digital point for 14, thus MATHEMATICA is sure
> that 14 is 14, and not 13.85 or 14.45 sumthing else, and it finds 100
> points. If you add only a digital point like this
> N[420900/14., 100]
> you will have the first result.

Thank you to all of you. This explains it.
-- 
Per Erik Rønne