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Write a − 1 for a = [ 2 5 1 3 ] - Mathematics

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प्रश्न

Write \[A^{- 1}\text{ for }A = \begin{bmatrix}2 & 5 \\ 1 & 3\end{bmatrix}\]

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उत्तर

\[\left| A \right| = \begin{vmatrix}2 & 5 \\ 1 & 3\end{vmatrix} = 1 \neq 0\]
\[\text{ Let }C_{ij}\text{ be the cofactor of }a_{ij}\text{ in A . }\]
The cofactors of element A are given by
\[ C_{11} = 3\]
\[ C_{12} = - 1\]
\[ C_{21} = - 5\]
\[ C_{22} = 2\]
\[adj A = \begin{bmatrix}3 & - 1 \\ - 5 & 2\end{bmatrix}^T = \begin{bmatrix}3 & - 5 \\ - 1 & 2\end{bmatrix}\]
\[\left| A \right| = 6 - 5 = 1\]
\[ \therefore A^{- 1} = \frac{1}{\left| A \right|}adj A = \begin{bmatrix}3 & - 5 \\ - 1 & 2\end{bmatrix}\]

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अध्याय 7: Adjoint and Inverse of a Matrix - Exercise 7.3 [पृष्ठ ३६]

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आरडी शर्मा Mathematics [English] Class 12
अध्याय 7 Adjoint and Inverse of a Matrix
Exercise 7.3 | Q 28 | पृष्ठ ३६

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