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Re: Strange results from Integrate

  • To: mathgroup at smc.vnet.net
  • Subject: [mg16084] Re: Strange results from Integrate
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Thu, 25 Feb 1999 08:24:49 -0500
  • Organization: Universitaet Leipzig
  • References: <7alq9j$nt9@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi Serigo,

Integrate[] will use the low precision numbers you enter.
If you type just 12.5 you have only 16 digits and that is not
sufficient for the numeric of the final evaluation. Try


f[x_]:=Exp[-20*(x-12.5`256)]

Integrate[f[x],{x,12.6`256,Infinity}]

Hope that helps
  Jens

Sergio Terrazas wrote:
> 
> Dear mathgroupers:
> I was working with a probability density function when I got the following
> strange result:
> 
> f[x_]= Exp[-20 (x-12.5)]
> 
> Integrate[f[x],{x,12.6,Infinity}]
> 

snip snap snip snap ..

> What is going on?
> Is Integrate just unrelaiable with non exact numbers?? (Scary !!)
> 
> I will appreciate any comments from the insiders.
> Thanks in advance ( Oh! by the way, I an using v. 3.0.1 for windows)
> 
> Sergio Terrazas
> Juarez, Mexico


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