Find Vector Field Given The Curl

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Homework Help Overview

The problem involves finding a vector field \(\vec{A}(\vec{r})\) in three-dimensional space such that the curl of the vector field equals a specified expression. The context is rooted in vector calculus, specifically dealing with vector fields and their properties.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to solve the problem by breaking it down into partial differential equations derived from the curl operation. They also explore a trial-and-error method to propose a potential solution for the vector field.

Discussion Status

Some participants affirm the validity of the original poster's solution, while others express concern about the rigor of the approach. There is an acknowledgment of the acceptability of trial and error in solving such problems.

Contextual Notes

The original poster mentions their professor's strictness regarding solutions, indicating a possible constraint on the level of rigor expected in the response.

tazzzdo
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Homework Statement



Find a vector field [itex]\vec{A}[/itex]([itex]\vec{r}[/itex]) in ℝ3 such that:

[itex]\vec{\nabla} \times \vec{A}[/itex] = y2cos(y)e-y[itex]\hat{i}[/itex] + xsin(x)e-x2[itex]\hat{j}[/itex]

The Attempt at a Solution



I broke it down into a series of PDE's that would be the result of [itex]\vec{\nabla} \times \vec{A}[/itex]:

∂A3/∂y - ∂A2/∂z = y2cos(y)e-y

∂A3/∂x - ∂A1/∂z = -[-xsin(x)e-x2] (since the j component has a negative sign)

∂A2/∂x - ∂A1/∂y = 0

By a little trial and error I came up with:

A1 = zxsin(x)e-x2
A2 = -zy2cos(y)e-y
A3 = z

This can be verified that:

[itex]\vec{\nabla} \times \vec{A}[/itex] = y2cos(y)e-y[itex]\hat{i}[/itex] + xsin(x)e-x2[itex]\hat{j}[/itex]

Is this a valid answer then?
 
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Sure it is. Why would you think it isn't?
 
Lol my Vector Calc professor tends to be picky. I didn't know if there was a more "rigorous" way to do it. But if this works, then I'm fine.
 
tazzzdo said:
Lol my Vector Calc professor tends to be picky. I didn't know if there was a more "rigorous" way to do it. But if this works, then I'm fine.

Trial and error is a perfectly fine way to solve a problem like this.
 

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