Vector Calculus: Operator Questions Answered

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Discussion Overview

The discussion focuses on questions related to vector calculus operators, specifically the dot operator, the gradient operator, and the Laplacian applied to vector fields. Participants explore the definitions and implications of these operators in the context of vector fields.

Discussion Character

  • Technical explanation

Main Points Raised

  • One participant asks about the difference between the expressions ∇⋅F and F⋅∇, seeking clarification on their meanings and implications.
  • Another participant explains that ∇⋅F results in a scalar function derived from the partial derivatives of the components of F, while F⋅∇ acts as an operator involving the components of F and the derivatives.
  • There is a question about the interpretation of ∇²F for a vector field, with one participant stating it consists of the Laplacian applied to each component of the vector field.
  • A participant introduces the idea that f⋅∇ can be interpreted as the directional derivative in the direction of f, adding another layer to the discussion.

Areas of Agreement / Disagreement

Participants present differing explanations and interpretations of the operators, indicating that multiple views exist without a clear consensus on some aspects.

Contextual Notes

Some assumptions about the notation and definitions of vector calculus operators may not be explicitly stated, leading to potential misunderstandings. The discussion does not resolve all mathematical steps or implications of the operators.

Savant13
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I'm looking into vector calculus right now, and I have a few questions.

* is the dot operator

What is the difference between \nabla * F and F * \nabla ?

What is \nabla ^2 F, where F is a vector field?
 
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∇⋅F is ∂(F_x)/∂x + ∂(F_y)/∂y + ∂(F_z)/∂z which is a scalar function. F⋅∇ is (F_x)(∂/∂x) + (F_y)(∂/∂y) + (F_z)(∂/∂z) which is an operator.

∇²F for a vector field F is just the vector field with components ∇²(F_x), ∇²(F_y) and ∇²(F_z).
 
How did you get the symbols to work?
 
f*del can be thought of as the directional derivative in the direction of f
 

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