Differential Equations and Linear Algebra (4th Edition)

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

Chapter 4 - Vector Spaces - 4.11 Chapter Review - Additional Problems - Page 337: 42

Answer

See answer below

Work Step by Step

We are given $A=\begin{bmatrix} -4 & 0& 3\\ 0 & 10 & 13 \\ 6 & 5& 2 \\ -2 & 2 & 10 \end{bmatrix}$ We obtain rowspace $A=\begin{bmatrix} -4 & 0& 3\\ 0 & 10 & 13 \\ 6 & 5& 2 \\ -2 & 2 & 10 \end{bmatrix} \approx \begin{bmatrix} -4 & 0& 3\\ 0 & 10 & 13 \\ 0 & 11 & 32 \\ 0 & -4 & -17 \end{bmatrix} \approx \begin{bmatrix} -4 & 0& 3\\ 0 & 10 & 13 \\ 0 & 0 & 277 \\ 0 & 0 & 59 \end{bmatrix} \approx\begin{bmatrix} -4 & 0& 3\\ 0 & 10 & 13 \\ 0 & 0 & 277 \\ 0 & 0 & 0 \end{bmatrix} \\ rowspace (A)=\{(-4,0,3),(0,10,13),(0,0,277)\}$ And colspace $A= \begin{bmatrix} -4 & 0& 3\\ 0 & 10 & 13 \\ 0 & 0 & 277 \\ 0 & 0 & 0 \end{bmatrix} \approx \begin{bmatrix} -4 & 0& 0\\ 0 & 10 & 39 \\ 6 & 5 & 26 \\ -2 & 2 & 34 \end{bmatrix} \approx \begin{bmatrix} -4 & 0& 0\\ 0 & 10 & 0\\ 6 & 5 & -6.5 \\ -2 & 2 & -262 \end{bmatrix} \\ colspace (A)=\{(-4,0,6,-2),(0,10,5,2),(0,0,-6.5,-262)\}$ Thus the nullspace $(A)$ can be written as $Ax=0 \rightarrow \begin{bmatrix} -4 & 0& 3\\ 0 & 10 & 13 \\ 0 & 0 & 277 \\ 0 & 0 & 0 \end{bmatrix} \begin{bmatrix} x\\ y \\ z \end{bmatrix}= \begin{bmatrix} 0\\ 0 \\ 0\\0 \end{bmatrix} \\ \rightarrow x=y=z=0$ Consequently, the null space of the given matrix $A$ is $\{(0,0,0)\}$
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