Question

Determine whether the product of the matrices is defined in each case. If so, state the order of the product. RS, where $R=[r_{ij}{]}_{2\times 2},S=[s_{ij}{]}_{2\times 2}$

Answer 1

$R={\left[r_{ij}\right]}_{2\times 2},S={\left[s_{ij}\right]}_{2\times 2}$

Number of columns of $R=$ Number of rows of $S$

$\therefore RS$ is defined and the order of $RS$ is $2\times 2.$

Hence, the answer is $2\times 2.$