Differential Equations and Linear Algebra (4th Edition)

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

Chapter 2 - Matrices and Systems of Linear Equations - 2.4 Row-Echelon Matrices and Elementary Row Operations - Problems - Page 156: 21

Answer

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Work Step by Step

$\begin{bmatrix} 3 & 7 & 10\\ 2 & 3& -1 \\ 1 & 2 &1 \end{bmatrix} \approx^1\begin{bmatrix} 1 & 2 & 1\\ 2 & 3& -1 \\ 3 & 7 &10 \end{bmatrix} \approx^2 \begin{bmatrix} 1 & 2& 1\\ 0 & -1& -3 \\ 0 & 1 &7 \end{bmatrix} \approx^3 \begin{bmatrix} 1 & 2& 1\\ 0 & 1& 3 \\ 0 & 1 &7 \end{bmatrix} \approx^4 \begin{bmatrix} 1 & 0& -5\\ 0 & 1& 3 \\ 0 & 0 &4 \end{bmatrix} \approx^5 \begin{bmatrix} 1 & 0& -5\\ 0 & 1& 3 \\ 0 & 0 &1 \end{bmatrix} \approx^6 \begin{bmatrix} 1 & 0& 0\\ 0 & 1& 0 \\ 0 & 0 &1 \end{bmatrix} $ Rank (A)= 3 The last matrix is in a row-echelon form. $P_{13}$ $A_{12}(-2), A_{13}(-3)$ $M_2(-1)$ $A_{21}(-2),A_{23}(-1)$ $M_3(\frac{1}{4})$ $A_{31}(5), A_{32}(-3)$
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