Is the Inverse of a Diagonal Matrix Simply the Inverse of Its Elements?

In summary, the inverse of a diagonal matrix is a matrix that undoes the effects of the original diagonal matrix. It is calculated by taking the reciprocal of each element on the main diagonal, and it is important in various mathematical and scientific applications. All diagonal matrices can be inverted as long as none of the elements on the main diagonal are equal to 0. The inverse of a diagonal matrix can also be found using the "shortcut" method, which involves taking the reciprocal of the determinant and multiplying it by the matrix with the elements on the main diagonal flipped.
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is the inverse of a diagonal matrix always just calculated by taking the inverses of each number in the matrix?
 
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  • #2
What is the inverse of the 2 by 2 matrix all of whose entries are 1?

For some reason, I read "symmetric matrices" where the question was about "diagonal matrices".
 
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  • #3
Take a diagonal matric, mutliply it by the one you just made, what's the answer?
 
  • #4
thank you very much!
 

Related to Is the Inverse of a Diagonal Matrix Simply the Inverse of Its Elements?

1. What is an inverse of a diagonal matrix?

The inverse of a diagonal matrix is a matrix that when multiplied by the original diagonal matrix, results in the identity matrix. It is the "opposite" of the original matrix in the sense that it undoes the effects of the original matrix.

2. How is the inverse of a diagonal matrix calculated?

The inverse of a diagonal matrix is calculated by taking the reciprocal of each element on the main diagonal. This means that if the diagonal matrix has the form [a, b, c], the inverse matrix would have the form [1/a, 1/b, 1/c].

3. What is the importance of the inverse of a diagonal matrix?

The inverse of a diagonal matrix is important in many mathematical and scientific applications. It is often used in solving systems of linear equations, finding the eigenvalues and eigenvectors of a matrix, and in various optimization problems.

4. Can all diagonal matrices be inverted?

Yes, all diagonal matrices can be inverted as long as none of the elements on the main diagonal are equal to 0. If any element on the main diagonal is equal to 0, the matrix is not invertible.

5. How does the inverse of a diagonal matrix relate to the determinant?

The determinant of a diagonal matrix is equal to the product of the elements on the main diagonal. Therefore, the inverse of a diagonal matrix can be found by taking the reciprocal of the determinant and multiplying it by the matrix with the elements on the main diagonal flipped. This is known as the "shortcut" method for finding the inverse of a diagonal matrix.

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