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Matrices — MATHS STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceMATHSMatrices1 Mark
Question
If $A=\left[\begin{array}{rrr}1 & -2 & 1 \\ 2 & 1 & 3\end{array}\right]$ and $B=\left[\begin{array}{ll}2 & 1 \\ 3 & 2 \\ 1 & 1\end{array}\right]$, then $(A B)^T$ is equal to
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Answer

(b) : $A B=\left[\begin{array}{rrr}1 & -2 & 1 \\ 2 & 1 & 3\end{array}\right]\left[\begin{array}{ll}2 & 1 \\ 3 & 2 \\ 1 & 1\end{array}\right]=\left[\begin{array}{rr}-3 & -2 \\ 10 & 7\end{array}\right]$
$
\Rightarrow \quad(A B)^T=\left[\begin{array}{rr}
-3 & 10 \\
-2 & 7
\end{array}\right]
$

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