Showing that two 4x4 matrices are similar

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SUMMARY

The discussion focuses on demonstrating the similarity of two 4x4 matrices, A and B, defined as A = [0 -1 1 1, -1 1 0 0, 0 0 -1 1, 0 0 0 0] and B = [-0.5 -0.5 -0.5 -1.5, -0.5 1.5 0.5 -0.5, 0 0 -1 1, 0 0 0 0]. The key equation to establish similarity is AS = SB, where S is a non-singular invertible matrix. The discussion emphasizes that while finding S can be challenging for 4x4 matrices, it is crucial to note that S is not unique; any scalar multiple of a valid S will also satisfy the equation.

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  • Familiarity with the concept of matrix similarity.
  • Knowledge of non-singular matrices and their properties.
  • Basic linear algebra concepts, including matrix equations.
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  • Research methods for finding non-singular matrices that satisfy matrix equations.
  • Study examples of matrix similarity for 2x2 and 3x3 matrices to build foundational understanding.
  • Explore the implications of eigenvalues and eigenvectors in determining matrix similarity.
  • Investigate the properties of scalar multiples of matrices and their impact on matrix equations.
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Students and educators in linear algebra, particularly those tackling matrix similarity problems, as well as anyone interested in advanced matrix theory and applications.

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Homework Statement



Given two 4x4 Matrices
A = [0 -1 1 1, -1 1 0 0, 0 0 -1 1, 0 0 0 0] B = [-0.5 -0.5 -0.5 -1.5, -0.5 1.5 0.5 -0.5, 0 0 -1 1, 0 0 0 0]

I need to show that these two matrices are similar.


Homework Equations


A = SBS^-1
which simplifies to AS = SB


The Attempt at a Solution


I understand that I need to find a non-singular invertible matrix S that satisfies the equation: AS = SB, but I have spent many hours trying to find out how to find this matrix for a 4x4 matrix. In the text and in many of the online help pages, there are only examples of 2x2 matrices that have a very obvious matrix. I have not learned eigenvalues or eigenvectors yet, and do not wish to use them unless there really is no other way to show similarity.

Thanks for any responses, and I appreciate any help on this problem.
 
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It's a matrix equation. Name the elements of the matrix S (i.e. sij), multiply the matrices in order to obtain a system of equations, and see what happens.
 
just carring on from radou, S is not unique, if S is a solution, then so is 2S, so you just need to demonstrate any matrix that works
 

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