Question:
If $A=\left[\begin{array}{ll}2 & 3 \\ 5 & 7\end{array}\right]$, find $A+A^{T}$
Solution:
Given : $A=\left[\begin{array}{ll}2 & 3 \\ 5 & 7\end{array}\right]$
$A^{T}=\left[\begin{array}{ll}2 & 5 \\ 3 & 7\end{array}\right]$
Now,
$A+A^{T}=\left[\begin{array}{ll}2 & 3 \\ 5 & 7\end{array}\right]+\left[\begin{array}{ll}2 & 5 \\ 3 & 7\end{array}\right]$
$\Rightarrow A+A^{T}=\left[\begin{array}{ll}2+2 & 3+5 \\ 5+3 & 7+7\end{array}\right]$
$\Rightarrow A+A^{T}=\left[\begin{array}{cc}4 & 8 \\ 8 & 14\end{array}\right]$