Re: Integrating by parts....II
- To: mathgroup at smc.vnet.net
- Subject: [mg8786] Re: Integrating by parts....II
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Thu, 25 Sep 1997 12:26:20 -0400
- Organization: University of Western Australia
- Sender: owner-wri-mathgroup at wolfram.com
Adrean Webb wrote: > Can Mathematica still solve the function below? > > f[n] = Integrate[Cos[x]*E[-x^2]*HermiteH[n,x],{x,-Inf,Inf}] Yes. You can compute the set of integrals, Integrate[Cos[x]*E[-x^2]*HermiteH[n,x],{x,-Inf,Inf}] for arbitrary n using the Hermite generating function. See the Notebook below for details. (Select from Notebook[ down to ] inclusive and paste into a new Mathematica Notebook). Cheers, Paul ____________________________________________________________________ Paul Abbott Phone: +61-8-9380-2734 Department of Physics Fax: +61-8-9380-1014 The University of Western Australia Nedlands WA 6907 mailto:paul at physics.uwa.edu.au AUSTRALIA http://www.pd.uwa.edu.au/~paul God IS a weakly left-handed dice player ____________________________________________________________________ Notebook[{ Cell[TextData[{ "Using the Hermite generating function, ", Cell[BoxData[ \(TraditionalForm \`\(\[ScriptCapitalH](x, z) == \[Sum]\+\(n = 0\)\%\[Infinity]\(\(\( H\_n\)(x)\)\ z\^n\)\/\(n!\), \)\)]] }], "Text", Evaluatable->False, AspectRatioFixed->True], Cell[BoxData[ \(TraditionalForm \`\(\[ScriptCapitalH](x_, z_) = \[ExponentialE]\^\(2\ x\ z - z\^2\); \)\)], "Input", AspectRatioFixed->True], Cell[CellGroupData[{ Cell[BoxData[ \(TraditionalForm \`\(\(\[Integral]\_\(-\[Infinity]\)\%\[Infinity] \[ExponentialE]\^\(-x\^2\)\ \(cos(x)\)\ \(\[ScriptCapitalH](x, z)\) \[DifferentialD]x // Factor\) // ComplexExpand\) // TrigReduce\)], "Input", AspectRatioFixed->True], Cell[BoxData[ \(TraditionalForm\`\(\ at \[Pi]\ \(cos(z)\)\)\/\ at \[ExponentialE]\%4\)], "Output"] }, Open ]], Cell[CellGroupData[{ Cell[BoxData[ FormBox[ RowBox[{"%", FormBox[\(+\(O(z)\)\^5\), "TraditionalForm"]}], TraditionalForm]], "Input"], Cell[BoxData[ FormBox[ InterpretationBox[ RowBox[{ \(\ at \[Pi]\/\ at \[ExponentialE]\%4\), "-", \(\(\ at \[Pi]\ z\^2\)\/\(2\ \ at \[ExponentialE]\%4\)\), "+", \(\(\ at \[Pi]\ z\^4\)\/\(24\ \ at \[ExponentialE]\%4\)\), "+", InterpretationBox[\(O(z\^5)\), SeriesData[ z, 0, {}, 0, 5, 1]]}], SeriesData[ z, 0, { Times[ Power[ E, Rational[ -1, 4]], Power[ Pi, Rational[ 1, 2]]], 0, Times[ Rational[ -1, 2], Power[ E, Rational[ -1, 4]], Power[ Pi, Rational[ 1, 2]]], 0, Times[ Rational[ 1, 24], Power[ E, Rational[ -1, 4]], Power[ Pi, Rational[ 1, 2]]]}, 0, 5, 1]], TraditionalForm]], "Output"] }, Open ]] } ]