Differential Equations and Linear Algebra (4th Edition)

Published by Pearson
ISBN 10: 0-32196-467-5
ISBN 13: 978-0-32196-467-0

Chapter 7 - Eigenvalues and Eigenvectors - 7.2 General Results for Eigenvalues and Eigenvectors - Problems - Page 452: 17

Answer

See below

Work Step by Step

1. Find eigenvalues: (A-$\lambda$I)$\vec{V}$=$\vec{0}$ $\begin{bmatrix} 2-\lambda & 3 \\ 2 & 1-\lambda \end{bmatrix}\begin{bmatrix} v_1\\ v_2 \end{bmatrix}=\begin{bmatrix} 0\\ 0 \\ 0 \end{bmatrix}$ $\begin{bmatrix} 2-\lambda & 3 \\ 2 & 1-\lambda \end{bmatrix}=0$ $\left (\lambda -4\right ) ( \lambda +1)=0$ $\lambda_1=4, \lambda_2=-1$ 2. Find eigenvectors: For $\lambda=4$ let $B=A-\lambda_1I$ $B=\begin{bmatrix} 2-\lambda & 3 \\ 2 & 1-\lambda \end{bmatrix}=\begin{bmatrix} -2 & 3 \\ 2 & -3 \end{bmatrix}$ We obtain reduced row echelon form: $\begin{bmatrix} -2 & 3 | 0 \\ 2 & -3 | 0 \end{bmatrix} \approx \begin{bmatrix} 2 & -3 | 0 \\ 0 &0 | 0 \end{bmatrix}$ Then, $B\vec{V}$=$\vec{0}$ Let $r$ be a free variable. $\vec{V}=r(2,3) \\ E_2=\{r(2,3)\} \rightarrow dim(E_2)=1$ For $\lambda=-1$ let $B=A-\lambda_1I$ $B=\begin{bmatrix} 2-\lambda & 3 \\ 2 & 1-\lambda \end{bmatrix}=\begin{bmatrix} 3 & 3 \\ 2 & 2 \end{bmatrix}$ We obtain reduced row echelon form: $\begin{bmatrix} 3 & 3 | 0 \\ 2 & 2| 0 \end{bmatrix} \approx \begin{bmatrix} 1 & 1 | 0 \\ 0 &0 | 0 \end{bmatrix}$ Then, $B\vec{V}$=$\vec{0}$ Let $r$ be a free variable. $\vec{V}=r(1,1) \\ E_2=\{r(1,1)\} \rightarrow dim(E_2)=1$ Hence, matrix $A$ is non-defective.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.