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If the matrix $A=\begin{bmatrix}5 & 4a+6\\a+12 & a+3\end{bmatrix}$ is a symmetric matrix, then the value of a is : |
2 5 -2 3 |
2 |
The correct answer is Option (1) → 2 As 'A' is a symmetric matrix, $A=A^T$ $⇒\begin{bmatrix}5 & 4a+6\\a+12 & a+3\end{bmatrix}=\begin{bmatrix}5 & a+12\\4a+6 & a+3\end{bmatrix}$ $⇒4a+6=a+12$ $⇒3a=6$ $⇒a=2$ |
