Can the Determinant of Similar Matrices be Proven Equal?

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Homework Help Overview

The discussion revolves around proving that the determinants of similar matrices are equal. The original poster expresses uncertainty about how to initiate the proof, specifically regarding the properties of determinants and the definition of similar matrices.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the definition of similar matrices and consider how properties of determinants might apply. The original poster contemplates a formula for the determinant but feels unsure about their approach. Others suggest focusing on the definition and properties of determinants to build the proof.

Discussion Status

The conversation has progressed with some participants providing guidance on the definition of similar matrices and the application of determinant properties. A specific approach to the proof has been articulated, leading to a conclusion about the equality of the determinants, although the original poster remains uncertain about their initial steps.

Contextual Notes

The original poster indicates a lack of confidence in their understanding and approach to the problem, highlighting the challenge of starting the proof without clear direction.

Dustinsfl
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Show that if A and B are similar matrices, then the det(A)=det(b).

I am not entirely sure how to start this proof.
I was thinking...
A=ai j

det(A)=[tex]\sum[/tex]ai j*(-1)i+j*Mi j from j=1 to n.

I am pretty much clueless on this one though and not sure if I am just throwing stuff on the wall hoping something will stick
 
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Write down the definition of similar matrices. What do you know about determinants that you can apply to that equation?
 
Matrix A is similar to B if there exists S such that B=S-1*A*S
 
det(B)=det(S-1*A*S)=det(S-1)det(A)det(S)=det(S-1*S)det(A)=det(I)det(A)=det(A) thus, det(B)=det(A)

Remarkable easy.
 
Good job!
 

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