Solving AxB = (B-1A-1)-1: Inverse Matrix Proof

In summary, the conversation is about finding x in the equation AxB = (B-1A-1)-1. The speaker is struggling with the assignment and their friend suggested that x is the identity matrix, but cannot prove it. They are seeking tips on how to solve the problem.
  • #1
Cannonstar
1
0
I'm having a bit of a struggle with my assignment.

I'm supposed to find what is x in AxB = (B-1A-1)-1 .

I'm stumped at what to do with this. My friend said that x is I (identity matrix), but he is unable to prove it as well. My linear algebra class just recently started doing this topic and I haven't fully absorbed the subject yet.

Any hints or tips would be helpful though.

Thanks!
 
Physics news on Phys.org
  • #2
Hi, you should try to simplify the right hand side, starting with the outermost -1. What rules do you have for the inverse of a product of matrices?
 
  • #3
(B-1A-1)-1 is the matrix C such that C(B-1A-1)= I. Since you have that equal to AxB, how do you get AxB(B-1A-1)= I??
 

1. What is an inverse matrix?

An inverse matrix is the matrix that when multiplied with the original matrix, results in the identity matrix (a square matrix with 1s on the main diagonal and 0s elsewhere).

2. Why is finding the inverse matrix important?

Finding the inverse matrix is important because it allows us to solve equations involving matrices, which are commonly used in scientific and mathematical fields. It also helps us to find the solutions to systems of linear equations.

3. What is the process for finding the inverse matrix?

The process for finding the inverse matrix involves using Gaussian elimination or Gauss-Jordan elimination to transform the original matrix into a reduced row-echelon form. From there, we can use the augmented matrix to find the inverse matrix.

4. How do we prove that AxB = (B-1A-1)-1?

To prove this, we can use the definition of the inverse matrix and the properties of matrix multiplication. We can show that when AxB is multiplied with (B-1A-1)-1, the result is the identity matrix, which proves that they are indeed inverses of each other.

5. Are there any special cases where a matrix does not have an inverse?

Yes, a matrix does not have an inverse if it is not a square matrix or if its determinant is equal to 0. In these cases, the matrix is said to be singular and does not have an inverse.

Similar threads

I Can't understand a step in an LU decomposition proof
    • Linear and Abstract Algebra
Replies
1
Views
1K
Prove the identity matrix is unique
    • Precalculus Mathematics Homework Help
2
Replies
57
Views
3K
Efficient Solution for (A+pI)x=b: Fast Matrix Inversion
    • Linear and Abstract Algebra
Replies
2
Views
2K
Finding Inverse Matrix by Definition
    • Linear and Abstract Algebra
Replies
1
Views
2K
Simple Proofs for Matrix Algebra Properties: A Beginner's Guide
    • Linear and Abstract Algebra
Replies
4
Views
2K
Finding the inverse of an m*n matrix
    • Linear and Abstract Algebra
Replies
2
Views
9K
Inverse Kinematics of a 6 DOF Robotic Arm
    • Engineering and Comp Sci Homework Help
Replies
1
Views
4K
Linear Algebra: Matlab Question
    • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
Solve Ax=b Matrix System of Equations: Help Needed
    • Linear and Abstract Algebra
Replies
1
Views
2K
Solving Ax=b; when to use LU decomposition?
    • Linear and Abstract Algebra
Replies
8
Views
11K

Hot Threads

Recent Insights

Back
Top