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Using elementary transformations, find the inverse of each of the matrices, if it exists
in Exercises 1 to 17.

    Q13.    \begin{bmatrix} 2 & -3\\ -1 & 2 \end{bmatrix}

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A=\begin{bmatrix} 2 & -3\\ -1 & 2 \end{bmatrix}

                A=IA

\Rightarrow          \begin{bmatrix} 2 & -3\\ -1 & 2 \end{bmatrix} = \begin{bmatrix}1&0\\0&1 \end{bmatrix}A

             R_2\rightarrow 2R_2+R_1

\Rightarrow      \begin{bmatrix} 2 & -3\\ 0 &1 \end{bmatrix}= \begin{bmatrix}1&0\\1&2 \end{bmatrix}A

\Rightarrow          R_1\rightarrow R_1+3R_2

\Rightarrow          \begin{bmatrix} 2 & 0\\ 0 &1 \end{bmatrix}= \begin{bmatrix}4&6\\1&2 \end{bmatrix}A

                R_1\rightarrow \frac{R_1}{2}

\Rightarrow          \begin{bmatrix} 1 & 0\\ 0 &1 \end{bmatrix}= \begin{bmatrix}2&3\\1&2 \end{bmatrix}A

so the inverse of matrix A is 

\therefore A^{-1}=\begin{bmatrix}2&3\\1&2 \end{bmatrix}.

 

Posted by

seema garhwal

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