Vector field dot product integration

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Homework Help Overview

The problem involves calculating the vector field F as the gradient of a scalar potential V, specifically V(x,y,z) = xye^z. The task includes evaluating the line integral of F along two different curves: one from the point (1,1,0) to (3,e-1) and another along the boundary of a square in the xy-plane.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss how to select a curve for the line integral and question the implications of using "any curve." There is uncertainty about the independence of the path and the conditions under which it applies. Some participants express confusion about the relationship between the potential function and the line integral.

Discussion Status

The discussion is ongoing, with participants raising questions about the interpretation of the problem, particularly regarding the notation and the orientation of the square. Some guidance has been provided regarding the independence of the integral from the path and the conditions for a potential function, but no consensus has been reached.

Contextual Notes

There are concerns about potential typographical errors in the problem statement, specifically regarding the coordinates of the endpoint and the orientation of the square. Participants also note the absence of the z variable in the context of the square boundary.

Unart
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Homework Statement


Calculate F=∇V, where V(x,y,z)= xye^z, and computer ∫F"dot"ds, where
A)C is any curve from (1,1,0) to (3,e-1)
B)C is a the boundary of the square 0≤x≤1, 0≤y≤1... oriented counterclockwise.

Homework Equations


∫F"dot"ds= ∫F(c(t)"dot"c'(t)


The Attempt at a Solution



So my question is how do I pick a curve from the two dots? And, how is it different from a square?
 
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Unart said:

Homework Statement


Calculate F=∇V, where V(x,y,z)= xye^z, and computer ∫F"dot"ds, where
A)C is any curve from (1,1,0) to (3,e-1)
B)C is a the boundary of the square 0≤x≤1, 0≤y≤1... oriented counterclockwise.

Homework Equations


∫F"dot"ds= ∫F(c(t)"dot"c'(t)

The Attempt at a Solution



So my question is how do I pick a curve from the two dots? And, how is it different from a square?

Doesn't the suggestion to use "any curve" suggest that it doesn't matter what curve you use? Is that the case in this problem? What do you know about independence of path and potential functions etc.?
 
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I know that the V(Q)-V(P) should equal the integral for F dot ds along any path. And that's about it. How to approach it I'm confused...
Do I just, do the subtraction of products of the function? Or, do I have to invent a curve too...

How would I approach the square when the z variable isn't mentioned.

This is my first time doing this.
 
Unart said:

Homework Statement


Calculate F=∇V, where V(x,y,z)= xye^z, and computer ∫F"dot"ds, where
A)C is any curve from (1,1,0) to (3,e-1)

That is an obvious typo. Does it mean (3,e,-1) or what?

B)C is a the boundary of the square 0≤x≤1, 0≤y≤1... oriented counterclockwise.

Oriented counterclockwise when viewed from where? Above or below the xy plane? And I suppose z = 0??

Homework Equations


∫F"dot"ds= ∫F(c(t)"dot"c'(t)


The Attempt at a Solution



So my question is how do I pick a curve from the two dots? And, how is it different from a square?

Unart said:
I know that the V(Q)-V(P) should equal the integral for F dot ds along any path.
[If the integral is independent of path] And that's about it. How to approach it I'm confused...
Do I just, do the subtraction of products of the function? Or, do I have to invent a curve too...

How would I approach the square when the z variable isn't mentioned.

This is my first time doing this.

First you have to check whether your integral is independent of path and the vector field has a potential function. What is the test for that? And if it does have a potential function ##\Phi## then, yes, the value of the integral is the difference of ##\Phi## at the end points.
 
It does... the function is continuous...
 
LCKurtz said:
That is an obvious typo. Does it mean (3,e,-1) or what?
Oriented counterclockwise when viewed from where? Above or below the xy plane? And I suppose z = 0??First you have to check whether your integral is independent of path and the vector field has a potential function. What is the test for that? And if it does have a potential function ##\Phi## then, yes, the value of the integral is the difference of ##\Phi## at the end points.

Unart said:
It does... the function is continuous...

Just because a vector field is continuous doesn't mean it has a potential function. There are theorems about gradients and curls and potential functions. What do they tell you for this problem?

[Edit, added]: Have you had the "fundamental theorem of calculus for line integrals"?$$
\int_P^Q \nabla \Phi \cdot d\vec R=\, \, ?$$
 
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