Integrating a curve of position vectors

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Discussion Overview

The discussion revolves around the integration of curve position vectors, specifically exploring whether it is possible to express a vector integral in terms of the information from the vector being integrated. Participants discuss concepts related to derivatives, including circular and tangent/normal components, and reference the Frenet-Serret formulas.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions if it is possible to express a vector integral using only the information from the vector itself, similar to how derivatives can be expressed.
  • Another participant requests explicit examples of curves and how circular and tangent/normal components are utilized in this context.
  • A participant mentions the Frenet-Serret frame and expresses uncertainty about its application in their exploration of vector integrals.
  • One participant describes their approach to deriving expressions for derivatives and integrals of vectors, involving angle and magnitude adjustments based on specific quantities.
  • There is a suggestion that deriving is "lossy," implying challenges in reversing the process to obtain integrals from derivatives without using sum or integral operators.
  • A participant shares their derived expressions for the derivative and integral of a vector, providing mathematical formulations that depend on the same quantities but differ in their operations.
  • Another participant mentions a user who may have insights on the topic due to their published work on derivatives.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether it is possible to express vector integrals in the desired manner. The discussion remains unresolved, with multiple viewpoints and uncertainties present.

Contextual Notes

Participants express varying levels of familiarity with the Frenet-Serret formulas and the mathematical expressions they are developing, indicating potential limitations in their understanding or application of these concepts.

rabbed
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I'm looking at different ways to express the derivative a curve, like circular and tangent/normal components.
Is there no such way that let's you express a vector integral in terms of information from the vector you want to integrate?
 
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Can you provide some explicit examples for your curve and how you use circular and tangent/normal components?

My understanding is that you are referring to the Frenet Serret formula of a space curve is that right?

https://en.wikipedia.org/wiki/Frenet–Serret_formulas

Can you provide a context for the vector integral you're thinking about?
 
No specific example at the moment, but I wanted some opinions if it would definitely be impossible or not.
Yeah, the Frenet Serret frame has come up in my searches, though I haven't investigated it yet.

I was able to create an expression for the derivative of a vector where I'm adding an angle value to the vector angle
and dividing a magnitude value with the vector length. Both values depend on x(t)*y'(t) - y(t)*x'(t) and x(t)*x'(t) + y(t)*y'(t).
Then I did the same for the integral of a vector, this time subtracting the same angle value and dividing the same magnitude
value by the length of the vector to be integrated. The values depended on the same quantities, but this time I had to integrate
the rectangular components: X(t)*y(t) - Y(t)*x(t) and X(t)*x(t) + Y(t)*y(t).

Expressions of derivatives depend on information of what is derivated, but is it impossible to write expressions of integrals depending on information of what is integrated (and without a sum/integral operator)?
I guess it boils down to that derivating is "lossy", so we can make chain, product rules for it, but not how to go the other way (in all cases)?
 
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This is what I got:

derivative of (x(t), y(t)) = l(t)/sqrt(x(t)^2 + y(t)^2) * (cos( atan2(y(t),x(t))+a(t) ), sin( atan2(y(t),x(t))+a(t) ))
where
l(t) = sqrt( (x(t)*y'(t) - y(t)*x'(t))^2 + (x(t)*x'(t) + y(t)*y'(t))^2 )
a(t) = atan2( x(t)*y'(t) - y(t)*x'(t), x(t)*x'(t) + y(t)*y'(t) )

integral of (x(t), y(t)) = l(t)/sqrt(x(t)^2 + y(t)^2) * (cos( atan2(y(t),x(t))-a(t) ), sin( atan2(y(t),x(t))-a(t) ))
where
l(t) = sqrt( (X(t)*y(t) - Y(t)*x(t))^2 + (X(t)*x(t) + Y(t)*y(t))^2 )
a(t) = atan2( X(t)*y(t) - Y(t)*x(t), X(t)*x(t) + Y(t)*y(t) )
 
@fresh_42 may have some ideas here as he's published some excellent insight articles on the various forms of derivatives.
 
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