Integral of Exponential with Polynomial Argument

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Discussion Overview

The discussion focuses on finding the integral of an exponential function with polynomial arguments over finite limits, specifically the integrals \(\int_0^\pi \exp^{-a x^2 -b x^4} dx\) and \(\int_0^\pi \exp^{-a x^2 -b x^4} (x - x^3)dx\). The scope includes mathematical reasoning and potential numerical evaluation methods.

Discussion Character

  • Mathematical reasoning, Exploratory

Main Points Raised

  • One participant inquires about the evaluation of the integral \(\int_0^\pi \exp^{-a x^2 -b x^4} dx\).
  • Another participant suggests using Wolfram Alpha for evaluation.
  • A subsequent reply notes that Wolfram Alpha does not evaluate the first integral.
  • One participant proposes that there likely is no closed form solution for the integral in terms of parameters \(a\) and \(b\), and suggests substituting numerical values for \(a\) and \(b\) to facilitate numerical integration.
  • It is mentioned that there are various tools available for numerical integration.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the existence of a closed form solution for the integral, and multiple views on numerical evaluation methods are presented.

Contextual Notes

The discussion does not resolve the assumptions regarding the parameters \(a\) and \(b\) or the specific conditions under which the integrals are evaluated.

LayMuon
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How can I find an Integral of an exponential with Polynomial argument with finite limits:

<br /> <br /> \int_0^\pi \exp^{-a x^2 -b x^4} dx \\<br /> <br /> \int_0^\pi \exp^{-a x^2 -b x^4} (x - x^3)dx<br /> <br />
 
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Doesn't evaluate the first one.
 
There likely is no closed form solution for the top one in terms of a and b. Put in numbers for a and b and there are a lot of tools that will integrate it numerically, including Wolfram Alpha.
 

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