Multiplying row exchange matrices

In summary, a row exchange matrix is a square matrix with 0s and 1s that is used to perform row operations on other matrices. It can be multiplied with other row exchange matrices to combine row operations. The purpose of using row exchange matrices is to make complex row operations more organized and efficient. They can also be used to solve systems of equations and have various real-world applications in fields such as computer graphics, physics, and economics.
  • #1
Arnoldjavs3
191
3

Homework Statement


Multiply these row excahnge matrices in the order pq qp and p^2
p =
[0 1 0]
[1 0 0]
[0 0 1]

q=
[0 0 1]
[0 1 0]
[1 0 0]

Homework Equations

The Attempt at a Solution


I don't understand why the solution is
[0 1 0]
[0 0 1]
[1 0 0]

do you not multiply rows by columns? When i do this i just get a 3x3 with 0s in the entire matrix. I don't understand, what am I doing wrong? Since this is a fundamental misunderstanding from my part.
 
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  • #2
nevermind I'm an idiot.

please delete/close
 
  • #3
Welcome to the club!
 

What is a row exchange matrix?

A row exchange matrix is a type of matrix that is used to perform row operations on other matrices. It is a square matrix with the same number of rows and columns, and it contains only 0s and 1s. Each row in the matrix represents a single row operation, such as swapping two rows or multiplying a row by a constant.

How do you multiply row exchange matrices?

To multiply row exchange matrices, you simply multiply them in the same way you would multiply two regular matrices. Each row in the resulting matrix will represent the combination of row operations from the two original matrices.

What is the purpose of using row exchange matrices?

Row exchange matrices are useful because they allow you to perform complex row operations on other matrices in a more organized and efficient manner. They also make it easier to keep track of the row operations that have been performed.

Can you use row exchange matrices to solve systems of equations?

Yes, row exchange matrices can be used to solve systems of equations. By performing row operations on the coefficient matrix, you can transform it into an upper triangular matrix, making it easier to solve for the variables.

What are some real-world applications of row exchange matrices?

Row exchange matrices are commonly used in computer graphics, particularly in 3D modeling and animation. They are also used in physics and engineering to solve systems of equations and in cryptography to encode and decode messages. Additionally, row exchange matrices have applications in economics, biology, and other fields that involve analyzing and manipulating large sets of data.

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