Jacobian in change of coordinates

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Discussion Overview

The discussion revolves around the role of the Jacobian in the context of changing coordinates for multiple integrals, exploring its connections to linear transformations and volume changes in both linear and nonlinear calculus.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants propose that the Jacobian is essential for changing bounds of integration in multiple integrals, linking multivariable calculus to linear algebra.
  • One participant mentions that if S is a region in R^n and T is a linear map, the volume of T(S) equals the volume of S times the determinant of T, suggesting a relationship between linear maps and volume.
  • Another participant emphasizes the connection between linear analysis, Jacobians, and integration, noting that these concepts arise from measure theory and Lebesgue integrals.
  • It is noted that in linear algebra, the determinant measures volume change under a linear map, while in nonlinear calculus, integrating different determinant functions at various points measures volume change under a nonlinear map.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and interpretation of the initial question, indicating some disagreement on the clarity and intent of the inquiry regarding the Jacobian and its implications.

Contextual Notes

Some assumptions about the nature of linear and nonlinear transformations, as well as the specific properties of the Jacobian, remain implicit and are not fully explored in the discussion.

Simfish
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So in the change of coordinates equation for multiple integrals, we have the Jacobian which allows us to change our bounds of integration.

It's the connection between multivariable calculus and linear algebra.

is this possible since the linear transformation allows a one-to-one-mapping between one coordinate system and the other coordinate system? And is this precisely the reason why we can take the Jacobian of a multiple integral?
 
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I don't understand your question, but I will just say that it might be insightful for you to know that if S is a region of R^n and T is a linear map from R^n to R^n, then the volume of T(S) equals the volume of S times the determinant of T (as a matrix). (And also that a linear map sends little cubes to little parallelepipedes)
 
Simfishy said:
So in the change of coordinates equation for multiple integrals, we have the Jacobian which allows us to change our bounds of integration.

It's the connection between multivariable calculus and linear algebra.

is this possible since the linear transformation allows a one-to-one-mapping between one coordinate system and the other coordinate system? And is this precisely the reason why we can take the Jacobian of a multiple integral?

hard to see what you are really asking but it is true that linear analysis has a lot to do with Jacobian and Integration. It comes from the realm of Measure theory where you get all those results for Lebesgue integral on R^n and product measures...
 
in linear algebra a determinant measures the volume change under a linear map.

in non linear calculus, integrating the (different) determinant functions at different points measures volume change under a non linear map.
 
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