Showing determinant of product is product of dets for linear operators

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SUMMARY

The discussion focuses on proving that for normal linear operators A and B, the determinant of their product equals the product of their determinants, specifically that det(AB) = det(A)det(B). The participants emphasize the importance of the operators commuting with their adjoint, which allows for the eigenbases to form orthonormal sets. By selecting a convenient orthonormal basis, such as the standard Cartesian basis (i, j, k), the operators can be represented by the identity matrix, simplifying the proof.

PREREQUISITES
  • Understanding of normal linear operators and their properties
  • Knowledge of determinants and their properties in linear algebra
  • Familiarity with eigenvalues and eigenvectors
  • Concept of orthonormal bases in vector spaces
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  • Learn about the relationship between determinants and eigenvalues
  • Explore the concept of adjoint operators in linear algebra
  • Investigate the implications of orthonormal bases in various vector spaces
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This discussion is beneficial for students and professionals in mathematics, particularly those studying linear algebra, as well as anyone involved in theoretical physics or engineering where linear operators are applied.

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Homework Statement


Assume A and B are normal linear operators [A,A^{t}]=0 (where A^t is the adjoint)

show that det AB = detAdetB


Homework Equations





The Attempt at a Solution


Well I know that since the operators commute with their adjoint the eigenbases form orthonormal sets. I'm not really sure how to proceed though so any assistance would be appreciated.
 
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I think I've got a solution for this but I'm not sure if it's general enough.

So since each operators eigenbasis forms an orthonormal set you can choose any convenient orthonormal basis. If I pick the standard cartesian basis (i,j,k) then each operator can be represented by the identity matrix. From here it is straight forward to show the identity.
 

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