Stable matrices and their determinants

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The discussion focuses on the stability of the zero state in a dynamical system defined by the equation x(t+1) = Ax(t), where A is a real n x n matrix. It explores the implications of the determinant of matrix A on stability, specifically when |det(A)| is greater than or equal to one versus when it is less than one. The participant expresses uncertainty about the relationship between the determinant and stability, suggesting a preference for analyzing the system through eigenvalues and eigenvectors instead. The conversation emphasizes the need for clarity on how determinants influence stability in dynamical systems. Understanding this relationship is crucial for determining system behavior.
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Homework Statement


Consider a dynamical system x(t+1) = Ax(t),, where A is a real n x n matrix.
(a) If |det(A)| > or equal to one, what can you say about the stability of the zero state?
(b) If |det(A)| < 1, what can you say about the stability of the zero state?


Homework Equations





The Attempt at a Solution


I have worked with various matrices knowing if they are stable or not and the value of the determinants, but from what I can see, there exists no relation between the determinant and the stability of the matrix, so basically, where to go from here?
 
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I am used to look at such questions by taking the eigenvectors as basis.
Then everything is understood on the basis of simple numbers: the eigenvalues.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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