Transformation of vector components

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Discussion Overview

The discussion centers on the transformation of vector components between two coordinate systems, specifically addressing how to evaluate the relationship at a specific point in one of the coordinate systems. The scope includes mathematical reasoning and conceptual clarification regarding the evaluation of functions and their products in the context of vector transformations.

Discussion Character

  • Mathematical reasoning, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant presents a formula for transforming vector components and questions whether to evaluate the sum of functions first or to evaluate each separately at a specific point.
  • Another participant expresses confusion about whether there is a difference between the two proposed evaluation methods.
  • A third participant suggests that while the methods may not differ in general, complications could arise if the Jacobian or vector components behave unusually at the specified point.
  • A fourth participant interprets the evaluation methods as sharing any peculiarities that may arise, suggesting that both approaches would reflect the same behavior at the point of interest.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the two evaluation methods differ. Some express uncertainty and highlight potential complications, while others suggest that both methods yield the same result under normal conditions.

Contextual Notes

Participants note that the behavior of the Jacobian and vector components at the specific point could influence the evaluation, indicating that assumptions about their regularity may be critical.

kent davidge
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The components of a vector ##v## are related in two coordinate systems via ##v'^\mu = \frac{\partial x'^\mu}{\partial x^\sigma}v^\sigma##. When evaluating this at a specific ##x'(x_0) \equiv x'_0##, how should we proceed? ##v'^\mu(x'_0) = \frac{\partial x'^\mu}{\partial x^\sigma}(x_0)v^\sigma(x_0)## or ##v'^\mu(x'_0) = (\frac{\partial x'^\mu}{\partial x^\sigma}v^\sigma)(x_0)##?

That is, should we first work out the sum of the functions and then evaluate the product? Or can we evaluate each separately?
 
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I do not see difference. Do they differ ?
 
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anuttarasammyak said:
I do not see difference. Do they differ ?
Not in general, I think. However you might get into trouble if the Jacobian ##\frac{\partial x'^\mu}{\partial x^\nu}## or the components ##v^\sigma## have some weird behaviour at ##x_0##, but so that yet their combination is a function that is fine there.
 
I interpret the two,
[tex]F(x_0)G(x_o)=[F(x)G(x)]_{x=x_0}[/tex]
The both share weirdness if any.
 
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