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Re: Mathematica Weirdness

  • To: mathgroup at smc.vnet.net
  • Subject: [mg116705] Re: Mathematica Weirdness
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Thu, 24 Feb 2011 06:24:30 -0500 (EST)

You need to use more precision

N[Integrate[1000000*Exp[x^2 - 12*x]*x^14, {x, 0, 1}], 20]

2.7482124237345664276

NIntegrate[1000000*Exp[x^2 - 12*x]*x^14, {x, 0, 1}]

2.74821


Bob Hanlon

---- Steve Heston <sheston at rhsmith.umd.edu> wrote: 

=============
My question is why I get a negative integral of a positive 
function?

Integrate[1000000*Exp[x^2-12*x]*x^14,{x,0,1}]//N
Integrate[1000000*Exp[x^2-12*x]*x^14,{x,0.,1}]//N
NIntegrate[1000000*Exp[x^2-12*x]*x^14,{x,0,1}]

The first line gives a negative answer, while the second two lines give 
identical positive answers.  Something is strange here.

Steve

Steven L. Heston
Associate Professor
Finance Department
Robert H. Smith School of Business
4447 Van Munching Hall Van Munching Hall
University of Maryland
College Park, MD 20742-1815
301-405-9686 TEL
301-405-0359 FAX
sheston at rhsmith.umd.edu
http://www.rhsmith.umd.edu




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