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Paul Abbott Chebyshev Article

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  • Subject: [mg79699] Paul Abbott Chebyshev Article
  • From: Angela Kou <Akou at>
  • Date: Thu, 2 Aug 2007 03:48:13 -0400 (EDT)


I'm trying to test Paul Abbott's code in his article on integral 
equation solving using Chebyshev polynomials (Mathematica Journal 8(4)) 
but Mathematica keeps giving me an error when I get to NIntegrate.  This 
is the code:
n=4; xs = N[Cos[Range[0, 2 n] Pi/(2 n)], 20];
cs = Thread[Subscript[c, Range[0, n]]];
lhs = cs.Table[Subscript[T, 2 i] (xs), {i, 0, n}];
rhs = 1 + 1/Pi cs.Table[NIntegrate[Evaluate[Subscript[T, 2 i] (t)/((xs - 
t)^2 + 1)], {t, -1, 1}, WorkingPrecision ->20], {i, 0, n}];

the last line of code keeps giving me the error that "NIntegrate::inumr: 
The integrand (t Subscript[T,0])/(1+(1.0000000000000000000-t)^2) has 
evaluated to non-numerical values for all sampling points in the region 
with boundaries {{-1,0}}. >>

I'm not quite sure why this is the case?

Angela Kou

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