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Re: Precision of output

• To: mathgroup at smc.vnet.net
• Subject: [mg48209] Re: Precision of output
• From: kazimir04 at yahoo.co.uk (Kazimir)
• Date: Tue, 18 May 2004 04:16:17 -0400 (EDT)
• References: <c89q2f$t51$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

> N[4209/0.14,100] I get:
> 30064.3

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, ∞], 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.

Vlad