Re: Can't get Mathematica to evaluate correctly a difficult
- To: mathgroup at smc.vnet.net
- Subject: [mg111549] Re: Can't get Mathematica to evaluate correctly a difficult
- From: Peter Pein <petsie at dordos.net>
- Date: Wed, 4 Aug 2010 07:51:12 -0400 (EDT)
- References: <i3bd7l$pjr$1@smc.vnet.net>
Am Wed, 4 Aug 2010 09:51:49 +0000 (UTC) schrieb Damien Wyart <damien.wyart at free.fr>: > 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, > Hi Damien, use exact input and then evaluate with a precision greater than 22 : In[14]:= N[173746*Sin[10^22]+94228*Log[171/10]-78487*Exp[21/50],30] Out[14]= -1.34181895782961954970427868423*10^-12 or change the precision of the input: In[15]:= 173746*Sin[10^22]+94228*Log[17.1`30]-78487*Exp[0.42`30] Out[15]= -1.341818957830*10^-12 Peter