Integrate malfunction?
- To: mathgroup at smc.vnet.net
- Subject: [mg33860] Integrate malfunction?
- From: "Steve Story" <sbstory at unity.ncsu.edu>
- Date: Sat, 20 Apr 2002 02:49:51 -0400 (EDT)
- Organization: NC State University
- Sender: owner-wri-mathgroup at wolfram.com
I recently had to do an integral which should evaluate to be a very very
small quantity. The function is always positive, but the integral gives me a
negative number. I think this is a malfunction of some sort. Here's the
code:
amu = 1.661*10^-27
nitrogen = 28*amu
k = 1.381*10^-23
t = 1000
Integrate[
4 Pi ((nitrogen/(2 Pi k t))^(3/2)) x^2 Exp[(-1 nitrogen x^2)/(2 k t)], {x,
11000, Infinity}]
Out[13]= -5.878291776559734*10^-16
does anyone know why this is happening? i tried NIntegrate instead, but it
said:
General::"unfl": "Underflow occurred in computation."
thanks,
Steve Story
_______________
Steve Story
Polymer NEXAFS Research Group
411B Cox
North Carolina State University
1-919-515-8147
sbstory at unity.ncsu.edu
_______________
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