Find Vector Field Given The Curl

In summary: Just make sure to verify your solution afterwards.In summary, the conversation discusses finding a vector field in ℝ3 that satisfies a given PDE. The user breaks down the PDE into a series of equations and uses trial and error to come up with a valid solution. The conversation also mentions being cautious of possible mistakes and verifying the solution.
  • #1
tazzzdo
47
0

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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  • #2
Sure it is. Why would you think it isn't?
 
  • #3
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.
 
  • #4
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.
 

1. What is a vector field?

A vector field is a mathematical concept that assigns a vector to each point in a given space. It can be represented graphically as a set of arrows, with each arrow pointing in the direction of the vector and its length representing the magnitude of the vector.

2. How is the curl of a vector field defined?

The curl of a vector field measures the tendency of the field to rotate around a given point. It is defined as the circulation per unit area at that point, and is represented mathematically as the cross product of the gradient and the vector field.

3. Why is it important to find the vector field given the curl?

Finding the vector field given the curl is important in many real-world applications, including fluid dynamics, electromagnetism, and heat transfer. It allows us to understand the behavior of a vector field, and can help in predicting and analyzing various physical phenomena.

4. What are some methods for finding a vector field given the curl?

There are several methods for finding a vector field given the curl, including the Helmholtz decomposition, the Hodge decomposition, and the Poincaré lemma. These methods use different mathematical techniques to express the vector field in terms of its curl.

5. Can a vector field have more than one curl?

No, a vector field can only have one curl at a given point. This is because the curl is a unique mathematical property of the vector field at a specific point, and cannot have multiple values.

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