Integral of sqrt(x^2-a^2)exp(-x)

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SUMMARY

The integral of the function sqrt(x^2-a^2)exp(-x) does not yield a simple primitive function. Users suggest starting with the standard formula for integrating sqrt(x^2-a^2)dx, which involves logarithmic terms. Integration by parts is recommended, but it leads to further complex integrals of the form (x^2-a^2)^(n/2)exp(-x). For practical applications, numerical integration for fixed values of 'a' or expressing the integral in terms of a modified Bessel function of the first kind is advised.

PREREQUISITES
  • Understanding of integration techniques, particularly integration by parts.
  • Familiarity with the standard integral formula for sqrt(x^2-a^2)dx.
  • Knowledge of modified Bessel functions of the first kind.
  • Basic numerical integration methods.
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  • Research the standard integral formula for sqrt(x^2-a^2)dx.
  • Learn about modified Bessel functions of the first kind and their applications.
  • Explore numerical integration techniques for evaluating complex integrals.
  • Study integration by parts in depth, focusing on its application to exponential functions.
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Mathematicians, physics students, and anyone involved in advanced calculus or numerical analysis who seeks to understand complex integrals involving exponential decay and square root functions.

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New to the forum, thanks for having me.

I've looked in tables and tried Mathmatica but have not came
up with a formula for the integral over x of

sqrt(x^2-a^2)exp(-x)

If anyone could point me in the right direction I'd be appreciative.
Thanks
 
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\int\sqrt{x^2-a^2}e^{-x}dx

Integration by parts?

There is a standard formula for integrating \int\sqrt{x^2-a^2}dx (that involves logs which might help later with the exponential).

Haven't worked it out myself but that's where i'd start.
 
You won't be able to find a primitive.
 
yeah. wolfram didn't like it when i plugged it in.
 
Thanks for your help. Seems integration by parts will just require further integrals
of the form (x^2-a^2)^n/2 exp(-x). Maybe I'll just have to integrate numberially for fixed values of a.
 
The integral from a to infinity can be expressed in terms of a modified Bessel function of the first kind.
 

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