Linear Algebra Similar Matrices Problem

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SUMMARY

The discussion focuses on finding two 2 × 2 matrices A and B such that the product AB is not similar to the product BA. A key insight is that if AB equals the zero matrix while BA does not, then the two products are definitively not similar. The hint provided emphasizes that AB can be arranged to be zero, which is crucial for solving the problem. This leads to the conclusion that specific matrix examples must be identified to illustrate this property.

PREREQUISITES
  • Understanding of matrix multiplication and properties of similar matrices.
  • Familiarity with the concept of the zero matrix in linear algebra.
  • Knowledge of determinants and their significance in matrix similarity.
  • Basic skills in constructing and manipulating 2 × 2 matrices.
NEXT STEPS
  • Research examples of 2 × 2 matrices that yield a zero product when multiplied in one order.
  • Study the properties of similar matrices and the implications of matrix determinants.
  • Explore the concept of matrix similarity in greater depth, including necessary and sufficient conditions.
  • Learn about the implications of non-similar matrices in linear transformations.
USEFUL FOR

Students studying linear algebra, educators teaching matrix theory, and anyone interested in the properties of matrix multiplication and similarity.

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Homework Statement



Find two 2 × 2 matrices A and B such that AB fails to be similar to
BA. Hint: it can be arranged that AB is zero but BA is not.


Homework Equations



N/A


The Attempt at a Solution



If AB similar to BA, AB = S-1BAS for some S, so AB DNE S-1BAS?
Or maybe det(AB) DNE det(BA)
I'm really not sure how to do this without guess and check, which I also tried and failed at
 
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You aren't paying much attention to the hint. If AB=0 and BA is not zero, then they aren't similar. Look for a example of that.
 

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