Cross Products: Solve For A Given B z-hat

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In summary: Please don't do that!In summary, the conversation discusses finding A given B=grad(A) and one is given the z-component of B. The mathematical operation to find A is the anti-derivative or "indefinite" integral of the z-component of B. If the z-component of grad A is known to be 0, then A can be any function of x and y. The conversation also briefly mentions the concept of curl.
  • #1
Nusc
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Homework Statement


B = grad(A)

Find A
If one is given B z-hat

Homework Equations




The Attempt at a Solution



What mathematical operation would I apply to solve this?
 
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  • #2
Do you know what grad is?
[tex]B= \nabla A= \left(\frac{\partial}{\partial x}\hat{\textbf{x}} + \frac{\partial}{\partial y}\hat{\textbf{y}} + \frac{\partial}{\partial z}\hat{\textbf{z}}\right) A[/tex]
 
  • #3
By "one is given B z-hat" do you mean you are given only the z-component of grad A?
Then there are many solutions. For example, if we are given that the z-component of grad A, then A can be any function of x,y- as long as it has no dependence on z, the z-component of grad A is 0.

Since the grad of a function is a derivative, the "mathematical operation" you would use to find A is the anti-derivative or "indefinite" integral.
 
  • #4
HallsofIvy said:
By "one is given B z-hat" do you mean you are given only the z-component of grad A?


Then there are many solutions. For example, if we are given that the z-component of grad A, then A can be any function of x,y- as long as it has no dependence on z, the z-component of grad A is 0.

No

Since the grad of a function is a derivative, the "mathematical operation" you would use to find A is the anti-derivative or "indefinite" integral.
 
  • #5
SOrry folks I meant Curl
 
  • #6
Nusc said:
SOrry folks I meant Curl

You already have another thread on exactly the same question
 

1. What is a cross product?

A cross product is a mathematical operation that takes two vectors as inputs and produces a third vector that is perpendicular to both of the input vectors. It is denoted by the symbol "x" or "⨯" and the result is sometimes referred to as the vector product.

2. How do you solve for a given B in the z-hat direction?

To solve for a given B in the z-hat direction, you will need to use the cross product formula: A x B = |A| |B| sinθ, where A is the first vector, B is the second vector, and θ is the angle between them. In this case, you will set θ to 90 degrees since the vector B is in the z-hat direction. Then, rearrange the formula to solve for B.

3. What are some real-world applications of cross products?

Cross products are commonly used in physics and engineering to calculate torque, magnetic fields, and angular momentum. They are also used in computer graphics and animation to create 3D effects and rotations.

4. Can you solve for a given B if the vectors are not perpendicular?

Yes, you can still use the cross product formula to solve for a given B even if the vectors are not perpendicular. However, the resulting vector will not be in the z-hat direction and will have a magnitude and direction determined by the angle between the two input vectors.

5. Are there any other methods for finding a cross product besides using the formula?

Yes, there are other methods for finding a cross product such as using determinant matrices or using the properties of cross products, such as the fact that the result is perpendicular to both input vectors. However, using the formula is the most direct and common method for solving for a given B in the z-hat direction.

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