No idea how to word this. Finding the gradient with vector?

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Homework Help Overview

The discussion revolves around finding a function Λ using the equation involving the gradient and a vector A defined in terms of variables x, y, z, and t. The context appears to involve concepts from vector calculus and potentially gauge transformations.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to clarify the nature of vector A and its components, questioning whether they correspond to a matrix or vector. There is also discussion about the implications of assuming A is a vector and the resulting equations for Λ.

Discussion Status

Some participants have provided guidance on interpreting the problem and have suggested considering the equations derived from the gradient. Others have noted the need for a more complete statement of the problem, indicating that the original post may not fully capture the complexity of the issue.

Contextual Notes

There is mention of gauge transformations, suggesting that the problem may be part of a larger theoretical framework. Participants have expressed uncertainty about the notation and the completeness of the information provided in the original post.

Flucky
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Homework Statement


I need to find Λ using the equation below (I think).

Homework Equations


A [/B]+ Λ = 0

where A(x,y,z,t) = B\begin{pmatrix} x+y\\ x-y\\ 0 \end{pmatrix}

The Attempt at a Solution


Is this at all possible?
 
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Flucky said:

Homework Statement


I need to find Λ using the equation below (I think).

Homework Equations


A [/B]+ Λ = 0

where A(x,y,z,t) = B\begin{pmatrix} x+y\\ x-y\\ 0 \end{pmatrix}

The Attempt at a Solution


Is this at all possible?

I'm not sure about your notation, is A a matrix, or a vector? Do the three components x+y, x-y, 0 correspond to vector components, or matrix components?
 
stevendaryl said:
I'm not sure about your notation, is A a matrix, or a vector? Do the three components x+y, x-y, 0 correspond to vector components, or matrix components?

Sorry it is a vector. I was trying to mimic exactly how it is written in front of me.
 
stevendaryl said:
I'm not sure about your notation, is A a matrix, or a vector? Do the three components x+y, x-y, 0 correspond to vector components, or matrix components?

Assuming that you mean that A is a vector, then your problem is to find a function \Lambda(x,y,z) such that

\nabla \Lambda = -A = -B(x+y, x-y, 0)

That means that there are three equations for \Lambda:
  1. \frac{\partial}{\partial x} \Lambda = -B (x + y)
  2. \frac{\partial}{\partial y} \Lambda = -B (x - y)
  3. \frac{\partial}{\partial z} \Lambda = 0
 
stevendaryl said:
Assuming that you mean that A is a vector, then your problem is to find a function \Lambda(x,y,z) such that

\nabla \Lambda = -A = -B(x+y, x-y, 0)

That means that there are three equations for \Lambda:
  1. \frac{\partial}{\partial x} \Lambda = -B (x + y)
  2. \frac{\partial}{\partial y} \Lambda = -B (x - y)
  3. \frac{\partial}{\partial z} \Lambda = 0

To solve the equation \frac{\partial}{\partial x} \Lambda = -B (x + y), consider how you would solve the ordinary differential equation

\frac{d}{d x} \Lambda = -B x + c

where c is a constant? What's the most general solution?
 
stevendaryl said:
Assuming that you mean that A is a vector, then your problem is to find a function \Lambda(x,y,z) such that

\nabla \Lambda = -A = -B(x+y, x-y, 0)

That means that there are three equations for \Lambda:
  1. \frac{\partial}{\partial x} \Lambda = -B (x + y)
  2. \frac{\partial}{\partial y} \Lambda = -B (x - y)
  3. \frac{\partial}{\partial z} \Lambda = 0

Hmm I think I may have to post the question in full. My original post is just a small part of a bigger question (about Gauge transformations) so I am probably going about it wrong.
 
Flucky said:
Hmm I think I may have to post the question in full. My original post is just a small part of a bigger question (about Gauge transformations) so I am probably going about it wrong.
You should always include the full problem as well as your attempts to solve it.
 

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