(d) dim ker(A) = dim ker(B). Combine (b) and (c) to show that if A and B are similar matrices, then 2 (e) are similar as well. Show that if A and B are similar, then the matrices A – XIn and B – In (Hint: Take another look at the proof given in class that similar matrices have the same characteristic polynomial.) (f) of A (and therefore also of B), then the geometric multiplicity of A as an eigenvalue of A must equal the geometric multiplicity of A as an eigenvalue of B. Use your answers to the previous parts to conclude that if A is an eigenvalue

Linear Algebra: A Modern Introduction
4th Edition
ISBN:9781285463247
Author:David Poole
Publisher:David Poole
Chapter4: Eigenvalues And Eigenvectors
Section4.3: Eigenvalues And Eigenvectors Of N X N Matrices
Problem 24EQ
icon
Related questions
Question

questions d-f

7. Recall the following statement from class:
If A and B are similar matrices, then A and B have the same eigenvalues, each
occurring with the same algebraic and geometric multiplicities.
In this problem, we will complete the proof of this statement by showing that if A is an eigen-
value of A (and therefore also of B), then the geometric multiplicity of A as an eigenvalue
of A must equal the geometric multiplicity of A as an eigenvalue of B.
Suppose B = s-1AS, where A, B, and S are all n x n matrices. Show the
(a)
following two facts:
(i) if v is in ker(B), then Sv is in ker(A).
(ii) if w is in ker(A), then S-w is in ker(B).
Let v1, V2, . .., Vm be a basis of ker(B). Show that the vectors Sv1, Sv2,
Svm, which (by part (a)) are in ker(A), are linearly independent.
(b)
....
(Hint: Start by considering a nontrivial relation c1(Sv1)+c2(Sv2)+· ·+cm(Svm) = 0.
What happens if you multiply both sides of this relation by S-1?)
(c)
Show that the vectors Sv1, Sv2, ., Sv m span ker(A).
(Hint: Let w be a vector in ker(A). What can you say about S-lw?)
(d)
dim ker(A)
Combine (b) and (c) to show that if A and B are similar matrices, then
= dim ker(B).
(e)
Show that if A and B are similar, then the matrices A – XIn and B – XIn
are similar as well.
(Hint: Take another look at the proof given in class that similar matrices have the
same characteristic polynomial.)
(f)
of A (and therefore also of B), then the geometric multiplicity of A as an eigenvalue of
A must equal the geometric multiplicity of as an eigenvalue of B.
Use your answers to the previous parts to conclude that if is an eigenvalue
Transcribed Image Text:7. Recall the following statement from class: If A and B are similar matrices, then A and B have the same eigenvalues, each occurring with the same algebraic and geometric multiplicities. In this problem, we will complete the proof of this statement by showing that if A is an eigen- value of A (and therefore also of B), then the geometric multiplicity of A as an eigenvalue of A must equal the geometric multiplicity of A as an eigenvalue of B. Suppose B = s-1AS, where A, B, and S are all n x n matrices. Show the (a) following two facts: (i) if v is in ker(B), then Sv is in ker(A). (ii) if w is in ker(A), then S-w is in ker(B). Let v1, V2, . .., Vm be a basis of ker(B). Show that the vectors Sv1, Sv2, Svm, which (by part (a)) are in ker(A), are linearly independent. (b) .... (Hint: Start by considering a nontrivial relation c1(Sv1)+c2(Sv2)+· ·+cm(Svm) = 0. What happens if you multiply both sides of this relation by S-1?) (c) Show that the vectors Sv1, Sv2, ., Sv m span ker(A). (Hint: Let w be a vector in ker(A). What can you say about S-lw?) (d) dim ker(A) Combine (b) and (c) to show that if A and B are similar matrices, then = dim ker(B). (e) Show that if A and B are similar, then the matrices A – XIn and B – XIn are similar as well. (Hint: Take another look at the proof given in class that similar matrices have the same characteristic polynomial.) (f) of A (and therefore also of B), then the geometric multiplicity of A as an eigenvalue of A must equal the geometric multiplicity of as an eigenvalue of B. Use your answers to the previous parts to conclude that if is an eigenvalue
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 3 images

Blurred answer
Recommended textbooks for you
Linear Algebra: A Modern Introduction
Linear Algebra: A Modern Introduction
Algebra
ISBN:
9781285463247
Author:
David Poole
Publisher:
Cengage Learning
Algebra & Trigonometry with Analytic Geometry
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:
9781133382119
Author:
Swokowski
Publisher:
Cengage
Elementary Linear Algebra (MindTap Course List)
Elementary Linear Algebra (MindTap Course List)
Algebra
ISBN:
9781305658004
Author:
Ron Larson
Publisher:
Cengage Learning
College Algebra (MindTap Course List)
College Algebra (MindTap Course List)
Algebra
ISBN:
9781305652231
Author:
R. David Gustafson, Jeff Hughes
Publisher:
Cengage Learning