What is the solution to this heavy integral?

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Discussion Overview

The discussion centers around the evaluation of a specific integral involving a square root and rational function. Participants explore various methods for solving the integral, including substitutions and computational tools.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant presents the integral I=\int \frac{\sqrt{\sqrt{x^4+1}-x^2}}{x^4+1}\,{\rm dx} for evaluation.
  • Another participant suggests a substitution of x^2 =\sinh t, leading to a transformed integral I=\int \frac{\sqrt{\coth t -1}}{\cosh t}{}dt, and mentions the potential for Mathematica to provide a complicated expression involving elliptic integrals.
  • A third participant claims to have solved the integral after applying the suggested substitution.
  • Another participant asserts that the integral can be expressed in terms of elementary functions, though this claim is not substantiated with details.

Areas of Agreement / Disagreement

There is no clear consensus on the solution to the integral, as participants present differing views on its expressibility in terms of elementary functions versus elliptic integrals.

Contextual Notes

The discussion includes various assumptions related to the transformations and the capabilities of computational tools, which are not fully explored or resolved.

janhaa
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Try to solve this integral:

[tex]I=\int \frac{\sqrt{\sqrt{x^4+1}-x^2}}{x^4+1}\,{\rm dx}[/tex]
 
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Subbing [itex]x^2 =\sinh t[/itex] will give you something like this

[tex]I=\int \frac{\sqrt{\coth t -1}}{\cosh t}{}dt[/tex]

Feed it now to Mathematica. There's about 50% chances it will return a complicated expression in terms of elliptic integrals.
 
Nice substitution, I managed to solve it now.
Thanks
 
Apparently the integral is expressible in terms of elementary functions.
 

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