Get matrix A from a series of elementary matrices

In summary, to find the inverse of matrix A, you can use the theorem that states E1E2E3...EkA=I. Additionally, the identity (MN)^-1 = N^-1M^-1 can be helpful. It is also recommended to consult your text for methods on determining the inverse of an individual matrix, such as using the matrix of cofactors.
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Tom Salazar
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1. Get A from its inverse
IMG_20150802_115613.jpg
3. I believe it has something to do with the theorem that states: E1E2E3...EkA=I
 
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  • #2
There's an identity that says that ##(MN)^{-1} = N^{-1} M^{-1}## that would be useful here. You should also consult your text about how to determine the inverse of an individual matrix. They probably discuss the method that uses the matrix of cofactors.
 
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  • #3
fzero said:
There's an identity that says that ##(MN)^{-1} = N^{-1} M^{-1}## that would be useful here. You should also consult your text about how to determine the inverse of an individual matrix. They probably discuss the method that uses the matrix of cofactors.

Thank you very much!
 

1. What is a matrix?

A matrix is a rectangular array of numbers, symbols, or expressions arranged in rows and columns. It is commonly used in mathematics, physics, engineering, and other fields to represent and manipulate data.

2. What is an elementary matrix?

An elementary matrix is a square matrix that represents a single elementary row operation. These operations include multiplying a row by a non-zero constant, interchanging two rows, and adding a multiple of one row to another.

3. How can elementary matrices be used to obtain matrix A?

Matrix A can be obtained from a series of elementary matrices by multiplying them in the same order that the row operations were performed on the original matrix. This results in a new matrix that is equivalent to A.

4. Why is it useful to use elementary matrices to obtain matrix A?

Using elementary matrices allows for easier manipulation and calculation of matrices, especially when dealing with larger matrices. It also allows for a clear and systematic approach to solving systems of linear equations and finding inverse matrices.

5. Can elementary matrices be used to obtain matrix A in all cases?

No, elementary matrices can only be used to obtain matrix A if it is possible to reach A from the original matrix through a series of elementary row operations. If the original matrix is not row equivalent to A, then elementary matrices cannot be used to obtain A.

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