Multiplication of two diagonal matrix
let Matrix A =\[\begin{bmatrix}a&0&0\\0&b&0\\0&0&c\end{bmatrix}\]
and Matrix B=\[\begin{bmatrix}p&0&0\\0&q&0\\0&0&r\end{bmatrix}\]
Then the product AB = \[\begin{bmatrix}a*p&0&0\\0&b*q&0\\0&0&c*r\end{bmatrix}\]
Note - In generak AB not equal to BA but in case of diagonal it is so.
So here AB and BA bothe are equal.
