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If a = [ 1 2 3 − 1 ] a N D B = [ 1 − 4 3 − 2 ] , Find | a B |

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प्रश्न

If \[A = \begin{bmatrix}1 & 2 \\ 3 & - 1\end{bmatrix}\text{ and B} = \begin{bmatrix}1 & - 4 \\ 3 & - 2\end{bmatrix},\text{ find }|AB|\]

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उत्तर

\[A = \begin{bmatrix}1 & 2 \\ 3 & - 1\end{bmatrix}\] 
\[ \Rightarrow \left| A \right| = - 1 - 6 = - 7\] 
\[B = \begin{bmatrix}1 & - 4 \\ 3 & - 2\end{bmatrix}\] 
\[ \Rightarrow \left| B \right| = - 2 + 12 = 10\] 
\[\text{ If A and B are square matrices of the same order, then }\left| AB \right| = \left| A \right|\left| B \right| . \] 
\[ \Rightarrow \left| AB \right| = \left| A \right|\left| B \right| = - 7 \times 10 = - 70\] 

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अध्याय 5: Determinants - Exercise 6.6 [पृष्ठ ९०]

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आर.डी. शर्मा Mathematics Volume 1 and 2 [English] Class 12
अध्याय 5 Determinants
Exercise 6.6 | Q 12 | पृष्ठ ९०

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