Help taking a cross product of a matrix

In summary, the conversation is about taking the cross product of two matrices. The poster is seeking advice on how to do it and mentions that their professor has mentioned crossing two tensors in a graduate fluid mechanics course. They also mention taking the dot product of two tensors. However, there seems to be some confusion about whether this is a valid operation and the poster is hoping for more clarification in their upcoming lecture.
  • #1
member 428835
hey all

well the title says it all. if i want to take the cross product of two matrices, how do i do it? any help, advice, etc. is very appreciated!

thanks
 
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  • #2
I don't think there's a standard definition for the cross product of two matrices. How do you think that would work, or what would it mean (e.g. the cross product of two vectors gives a vector perpendicular to both; what would the cross product of two linear transformations be)?
 
  • #3
I'll take a stab: why do you want to take the cross product of two matrices, assuming such an animal exists?
 
  • #4
hey guys! ok, so let me explain the situation: I am in a graduate fluid mechanics course and we are dealing with tensors, which are matrices. my professor was reviewing div, del, grad, and the rest of the operators with the kronecker delta and permutation epsilon. he did mention crossing two tensors! he also mentions "dotting" or taking the dot product, of two tensors. but it seems if this is not a "thing" maybe he will elaborate in tomorrow's lecture?

thanks for both your helps! this explains why google couldn't really help me either
 
  • #5


Hello there,

To take the cross product of two matrices, you can use the following steps:

1. Make sure that the two matrices have the same number of rows and columns. If they do not have the same dimensions, the cross product cannot be computed.

2. Multiply the first matrix by the transpose of the second matrix. This will result in a new matrix with the same number of rows as the first matrix and the same number of columns as the second matrix.

3. Repeat the process, but this time multiply the second matrix by the transpose of the first matrix. This will result in a new matrix with the same number of rows as the second matrix and the same number of columns as the first matrix.

4. Subtract the two resulting matrices from each other. This will give you the cross product of the original two matrices.

I hope this helps! Let me know if you have any further questions. Good luck!
 

1. What is a cross product of a matrix?

A cross product of a matrix is a mathematical operation where two matrices are multiplied together to produce a new matrix. It is used to find the perpendicular vector to two given vectors in three-dimensional space.

2. How is a cross product of a matrix calculated?

To calculate the cross product of two matrices, you need to first determine the dimensions of the resulting matrix, which will be one row and one column. Then, use the formula:

[ax, ay, az] x [bx, by, bz] = [aybz - azby, azbx - axbz, axby - aybx]

Where a and b are the elements of the two matrices.

3. What are the properties of a cross product of a matrix?

The properties of a cross product of a matrix include being non-commutative, meaning the order of multiplication matters, and being distributive, meaning it can be distributed over addition or subtraction. It also follows the associative property, meaning the grouping of matrices being multiplied does not affect the result.

4. Why is a cross product of a matrix useful?

A cross product of a matrix is useful in various applications, such as computer graphics, physics, and engineering. It can help determine the direction and magnitude of a vector, calculate areas of polygons, and solve systems of equations.

5. Is there a different method for taking a cross product of a matrix?

Yes, there is another method called the geometric interpretation method. This method involves finding the area of a parallelogram formed by the two vectors and then taking the cross product of the two vectors to find the direction of the resulting vector. However, this method is more commonly used for vectors in two dimensions.

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