Is the Integral of sqrt(x^2 + y^2 + C^2) Solvable?

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Discussion Overview

The discussion revolves around the solvability of the integral of the function \(\sqrt{x^2 + y^2 + C^2}\), where \(C\) is a constant. Participants explore various methods of integration, including double integrals and substitutions, while addressing notation and the structure of the integrals involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant questions the solvability of the integral and notes that their calculator does not provide a formula independent of other integrals.
  • Another participant points out a potential notation issue regarding the placement of \(dy\) and \(dx\) in the integral.
  • Some participants clarify that the notation used is common, especially for nested integrals.
  • A suggestion is made to integrate \(\int \sqrt{t^2 + c} \, dt\) as a simpler step towards solving the original integral.
  • One participant proposes making a substitution to simplify the integral before proceeding with integration.
  • Another participant mentions using the Leibniz product rule for integration, suggesting a specific approach involving parts integration.
  • There is a correction regarding the notation of the integral, emphasizing the importance of including \(C^2\) and its non-zero status.

Areas of Agreement / Disagreement

Participants express differing views on the notation and methods for integration, with no consensus reached on the overall solvability of the integral. Multiple approaches are suggested, but the discussion remains unresolved regarding the best method to use.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the variables and constants involved, as well as the clarity of the notation used in the integral expressions.

Kruger
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I attached this integran (see picture). If I put this in my calculator he doesn't give me a formula independent of other integrals. Is this unsolveable? For you informations, C is a constant.
 

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hello there

in your diagram the intergrand is not being integrated dy and dx should be placed after
the intergrand, correct me if I am wrong

steven
 
That's a common notation especially when the integrals are nested (folded) deep. It's just:

[tex]\int\int \sqrt{x^2+y^2+C}dydx[/tex]
 
Do you know how to integrate:

[tex]\int \sqrt{t^2 + c} \, dt[/tex]

If you can do that the rest is pretty simple.
 
no, sorry I don't know how to integrate this. Can someone tell me please?
 
hello there

just make a substitution which forms a change of variable such that you get something much more simpler in which you are able to integrate, as for your double integral, once you have put the intergrand in the correct position you first integrate the inside then you will be left with one integral and then integrate the next, but for each integral you are only integrating with respect to one variable and so all other variables are treated as constants in the intergrand

take care

steven
 
Ok, I'll try it.
 
integrate it by the lebniz product rule. take one function as sqrt(t2 + c) and the other as one.
 
Yes,it's reccomendable to use part integration,because the sign of the unknown constant can be either plus or minus and one wouldn't know which sub (cosh or sinh) to make.

Daniel.
 
  • #10
That's a common notation especially when the integrals are nested (folded) deep. It's just:

[tex]\int\int \sqrt{x^2+y^2+C}dy \; dx[/tex]

You left of a square, it was actually

[tex]\int\int \sqrt{x^2+y^2+C^2}dydx[/tex]

which makes it easier (C^2 is nonzero).
 

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