Show companion matrix is similar to the following matrix

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Homework Help Overview

The discussion revolves around demonstrating that a given companion matrix is similar to another specified matrix. The context involves concepts from linear algebra, particularly matrix similarity and properties of companion matrices.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the relationship between the given matrix and the companion matrix, exploring the condition for similarity through the equation A = P^-1 * C * P. Questions arise regarding the characteristic and minimal polynomials of the matrices involved, as well as the construction of the rational canonical form.

Discussion Status

The discussion is active, with participants sharing insights about the characteristic polynomial and minimal polynomial. Some guidance has been offered regarding the properties of upper triangular matrices and their characteristic polynomials, but no consensus has been reached on the next steps or methods to find the necessary polynomials.

Contextual Notes

There is mention of specific properties that could indicate similarity, such as having the same minimal polynomial and Frobenius canonical form. However, participants express uncertainty about how to proceed with finding these polynomials.

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Homework Statement


need to show companion matrix is similar to the following matrix
F552C6O.jpg
(here is the picture of the matrix)

Homework Equations

here is the companion matrix
http://en.wikipedia.org/wiki/Companion_matrix

information on matrix similarity
http://en.wikipedia.org/wiki/Matrix_similarity

The Attempt at a Solution



say given matrix is A and companion matrix is C then need to show

A = P^-1 * C * P for some invertible matrix P

i guess i could reduce guesswork by rewriting as

P*A = C*P

but even then it does not seem to be the ideal way to go about things.
 
Last edited:
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I don't think you put in the right link to the matrix...
 
oh lol fixed
 
What is the characteristic and minimal polynomial of that matrix? Can you construct the rational canonical form based off of elementary divisors?
 
i know char for companion but that is all.

i also know:

if same minimal poly then similar

if same frobenius canonical form then similar

but no clue how to go about finding them
 
Since your matrix is upper triangular, finding the characteristic polynomial is easy: It is just ##∏ (x-\lambda_i)##. If you can show that this is the minimal polynomial as well, then you are done.
 

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