Understanding the Relationship Between r & $\hat{r}$ in a Vector Equation

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Discussion Overview

The discussion revolves around the relationship between the displacement vector \( \vec{r} \) and the unit vector \( \hat{r} \) in the context of a vector equation involving integrals. Participants explore the implications of using these vectors in a specific equation related to magnetic fields.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant expresses confusion about the difference between the displacement vector \( \vec{r} \) and the unit vector \( \hat{r} \) in a vector equation.
  • Another participant asserts that the second expression in the equation is correct while implying the first is not, without providing further details.
  • A subsequent post corrects a previous error regarding the exponent in the equation, indicating a misunderstanding in notation.
  • Another participant clarifies that \( \hat{r} \) is defined as \( \frac{\vec{r}}{r} \), suggesting a straightforward relationship between the two vectors.
  • One participant expresses regret for asking what they perceive as a simple question, indicating a concern about the clarity of their inquiry.

Areas of Agreement / Disagreement

There appears to be some disagreement regarding the correctness of the initial expression, with at least one participant asserting it is incorrect. However, the discussion does not reach a consensus on the implications of this disagreement.

Contextual Notes

Participants have not fully explored the implications of the definitions of \( \vec{r} \) and \( \hat{r} \), nor have they clarified the context in which these vectors are used in the equation.

Astrum
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I'm not sure I get how:[tex]\frac{\mu_{0}}{4\pi}\int_{C}\frac{I(d\vec{l}\times\vec{r})}{r^{3}}[/tex] = [tex]\frac{\mu_{0}}{4\pi}\int_{C}\frac{I(d\vec{l}\times\hat{r})}{r^{2}}[/tex]

the r is a displacement vector in the first, and in the second it's a unit vector, but why is this so?
 
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The second expression is correct, the first one is not.
 
Sorry, meant to put a cubed there. Fixed
 
There's nothing really to get: [itex]\widehat{r} = \frac{ \vec{r} }{r}[/itex].
 
I see,another dumb question I asked, sorry for wasting your time...
 

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