What is the relationship between A and A^TA?

  • Thread starter salman213
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In summary, A^TA represents the transpose of matrix A multiplied by matrix A, also known as the inner product or dot product of two matrices. To determine A^TA, you need to first transpose matrix A and then multiply it by matrix A using the rules of matrix multiplication. This operation is important in various applications such as solving linear equations and performing data analysis, and has properties such as being a symmetric matrix and having eigenvalues that are squared singular values of A. However, A^TA can only be determined if A is a square matrix, as the transpose of a non-square matrix and the matrix itself have different dimensions and cannot be multiplied together.
  • #1
salman213
302
1
3. a) Assume that A^−1 =

1 0 1
2 1 3
1 0 2

Determine the matrix A^TA
 
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  • #2
what is (A^-1)^-1
 
  • #3
Are these homework problems? If so, you should move these questions here. Note that "Homework Help" has some special rules, including this: you should show some work.
 
  • #4
nah it was on a past mid term that i was looking at i have a final coming up soon so i was just wondering but i figured it out after computing (A^-1)^-1

i guess that is A so I just take the transpose of that and multiply it by A
 

1. What does A^TA mean?

A^TA represents the transpose of matrix A multiplied by matrix A. This operation is also known as the inner product or dot product of two matrices.

2. How do you determine the matrix A^TA?

To determine A^TA, you need to first transpose matrix A by switching the rows and columns. Then, multiply the transposed matrix by matrix A using the rules of matrix multiplication.

3. Why is determining A^TA important?

Determining A^TA can be useful in various applications such as solving linear equations, finding eigenvectors and eigenvalues, and performing data analysis. It can also help in simplifying calculations and reducing the size of matrices.

4. What are the properties of A^TA?

Some of the properties of A^TA include: it is a symmetric matrix, its diagonal elements are the squared norms of the columns of A, and its eigenvalues are the squared singular values of A.

5. Can you determine the matrix A^TA if A is not a square matrix?

No, A^TA can only be determined if A is a square matrix. This is because the transpose of a non-square matrix and the matrix itself have different dimensions and cannot be multiplied together.

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