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Re: Can't get Mathematica to evaluate correctly a difficult

• To: mathgroup at smc.vnet.net
• Subject: [mg111541] Re: Can't get Mathematica to evaluate correctly a difficult
• From: "Niels R. Walet" <niels.walet at manchester.ac.uk>
• Date: Wed, 4 Aug 2010 07:33:58 -0400 (EDT)

Damien Wyart wrote:
> Hello,
>
> I am using Mathematica 7.0.2 and playing a bit with an expression
> analyzed in the following paper:
> http://www.loria.fr/~zimmerma/papers/cise.pdf
>
> I tried many constructions with N and SetPrecision and can't get
> Mathematica to output the correct result (I am not very experienced with
> Mathematica). Here is the expression :
>
> 173746*Sin[10^22]+94228*Log[17.1]-78487*Exp[0.42]
>
> The correct result should be -1.341818958*10^-12 but even forcing each
> term with N and a very large number, I am still not getting this value
> at all.
>
>
> Any help will be appreciated. Thanks in advance ; best regards,
>
>   
Use 30 digit precision on the reals:

173746*Sin[10^(22)]+94228*Log[17.1`30]-78487*Exp[0.42`30]

-1.341818957830*10^-12

-- 
Prof. Niels R. Walet                   Phone:  +44(0)1613063693
School of Physics and Astronomy        Fax:    +44(0)1613064303
The University of Manchester           Mobile: +44(0)7905438934
Manchester, M13 9PL,  UK               room 7.7, Schuster Building
email: Niels.Walet at manchester.ac.uk 
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