MathGroup Archive 2002

[Date Index] [Thread Index] [Author Index]

Search the Archive

another integral problem


Awhile ago I had a problem with a triple integral.  Now, I've got troubles
with a single integral.  I'm sure that it has something to do with 'how' Mathematica 
finds integrals, but if someone could clue me in...
Integrate[Abs[x^2 Cos[x]-x^3 + x,{x,0,1.1983}] and Integrate[Abs[x^2
Cos[x]-x^3 + x,{x,0,1.19836].  From appearance, you might guess that these
should be pretty close.  The first is pos., while the 2nd is neg, even
though the integrand is non-neg.  FYI, 1.1983 is an approx. to x^2
Cos[x]=x^3 -x.  What's interesting, is that when you use a 'better' approx.,
the result is neg.  Now, with NIntegrate, there is no problem.  Please
advise.

Bradley Stoll


  • Prev by Date: Re: Magic Matrices
  • Next by Date: Re: operating system
  • Previous by thread: Boundary layer equations
  • Next by thread: RE: another integral problem