Vector Triple Product Identity and Jacobi Identity for Deriving 4B.10 and 4B.11

In summary, the conversation discusses the use of vector triple product identity to derive results from 4B.8, specifically for determining the vectors ##\vec{L_R}## and ##\vec{S_R}##. However, after using the identity and finding the integrand to be ##\vec{E}(\vec{r}\cdot\vec{B}) - \vec{B} (\vec{r} \cdot \vec{E})##, the next best step suggested is to use the Jacobi identity. However, this also leads to the same integrand.
  • #1
TheCanadian
367
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Screen Shot 2016-05-18 at 2.57.39 PM.png


I was trying to derive the following results from 4B.8 as suggested by using the vector triple product identity but have been unsuccessful in deriving ##\vec{L_R}## and ##\vec{S_R}## in the end. After using the identity and finding the integrand to be ## \vec{E}(\vec{r}\cdot\vec{B}) - \vec{B} (\vec{r} \cdot \vec{E}) ## what would be the next best step to take to re-derive the 4B.10 and 4B.11?
 
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  • #2
TheCanadian said:
After using the identity and finding the integrand to be ## \vec{E}(\vec{r}\cdot\vec{B}) - \vec{B} (\vec{r} \cdot \vec{E}) ##
I haven't tried it, but my guess is that this is not the right identity to use, and that you should rather use the Jacobi identity that is a couple of lines below in the Wikipedia page.
 
  • #3
DrClaude said:
I haven't tried it, but my guess is that this is not the right identity to use, and that you should rather use the Jacobi identity that is a couple of lines below in the Wikipedia page.

Okay. I've looked into that identity as well now, and after using it, still don't quite get any further since it reduces back to the case of the integrand equalling ## \vec{E}(\vec{r}\cdot\vec{B}) - \vec{B} (\vec{r} \cdot \vec{E}) ##.
 

1. What is vector integration by parts?

Vector integration by parts is a mathematical technique used to solve integrals involving vector functions. It is similar to the traditional integration by parts method, but with vectors instead of just scalar values.

2. When is vector integration by parts used?

This method is often used when solving integrals involving vector fields, such as in physics and engineering problems. It is also used in vector calculus to solve line and surface integrals.

3. How does vector integration by parts work?

Vector integration by parts works by breaking down a vector integral into smaller parts and using the product rule to manipulate the integrand. This allows for the integral to be solved in a step-by-step process.

4. What is the formula for vector integration by parts?

The formula for vector integration by parts is given by ∫u dv = u v - ∫v du, where u and v are vector functions and du and dv are their differentials. This is similar to the traditional integration by parts formula, but with vectors instead of scalar values.

5. Are there any limitations to using vector integration by parts?

Yes, there are limitations to using vector integration by parts. This method is most effective when the vector functions involved have simple forms, such as polynomials or trigonometric functions. It may be more difficult to apply for more complex vector functions.

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