Solving Difficult Problem: $\partial x/\partial y$ as Function of x

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Discussion Overview

The discussion revolves around the mathematical problem of expressing \( y \) as a function of \( x \) given the equation \( \partial x/\partial y = A * [B/y + C/(y-D)]^{1/2} \). The focus is on the challenges associated with solving this equation, particularly in the context of elliptic integrals.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that replacing the partial derivative \( \partial x/\partial y \) with \( dx/dy \) and integrating both sides could express \( x \) in terms of an incomplete elliptic integral of \( y \).
  • Another participant agrees that solving for \( x \) as a function of \( y \) is straightforward, but expresses difficulty in solving for \( y \) as a function of \( x \).
  • A participant notes that if the integral is indeed elliptic, it represents a classic problem that has historically been challenging for mathematicians, mentioning that there is a known method to solve it.
  • There is a reference to the work of Ramanujan in relation to such problems, indicating the complexity and historical difficulty of the topic.
  • One participant expresses anticipation for further references or insights on the matter.

Areas of Agreement / Disagreement

Participants express a general agreement on the complexity of the problem and the potential connection to elliptic integrals, but there is no consensus on the methods or solutions available for expressing \( y \) as a function of \( x \).

Contextual Notes

The discussion highlights the unresolved nature of the problem, with participants acknowledging the historical challenges without providing definitive solutions or methods. There are also references to broader mathematical difficulties that remain unsolved.

redtree
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Given the following:

[tex]\partial x[/tex]/[tex]\partial y[/tex] = A * [B/y + C/(y-D)]^(1/2)

Solve for y as a function of x.
 
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Replacing the partial of x with respect to y with dx/dy, and moving the dy from the denominator of the l.h.s. to the numerator of the r.h.s., and then taking the indefinite integral of both sides, does not that express x in terms of an (incomplete) elliptic integral of y?
 
DeaconJohn said:
Replacing the partial of x with respect to y with dx/dy, and moving the dy from the denominator of the l.h.s. to the numerator of the r.h.s., and then taking the indefinite integral of both sides, does not that express x in terms of an (incomplete) elliptic integral of y?

Solving for x as a function of y is easy. It's just as you suggested. The hard part is solving for y as a function of x (at least for me).
 
Well, if it is an elliptic integral like I suspect, then that is a classic and difficult problem. Many very good mathematicians were unable to make any progress on it for many years. However, there is now a known method of solving it. That is, if I remember correctly. In any case, it's the kind of stuff Ramanujan was good at. I post a reference next time I run across one.

Nobody said mathematics was easy. Many elementary things are beyond our current grasp. Mathematicians don't even understand which integers in cyclotomic fields are units. It's because there are a lot of hard problems.
 
DeaconJohn said:
Well, if it is an elliptic integral like I suspect, then that is a classic and difficult problem. Many very good mathematicians were unable to make any progress on it for many years. However, there is now a known method of solving it. That is, if I remember correctly. In any case, it's the kind of stuff Ramanujan was good at. I post a reference next time I run across one.

Nobody said mathematics was easy. Many elementary things are beyond our current grasp. Mathematicians don't even understand which integers in cyclotomic fields are units. It's because there are a lot of hard problems.

Thanks. I look forward to it.
 

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