Question:
If $A=\left[\begin{array}{cccc}5 & -2 & 6 & 1 \\ 7 & 0 & 8 & -3 \\ \sqrt{2} & \frac{3}{5} & 4 & 3\end{array}\right]$ then write
i. the number of rows in $\mathrm{A}$,
ii. the number of columns in $A$,
iii. the order of the matrix $\mathbf{A}$,
iv. the number of all entries in A,
v. the elements $a_{23}, a_{31}, a_{14}, a_{33}, a_{22}$ of $A$.
Solution:
(i) Number of rows $=3$
(ii) Number of columns $=4$
(iii) Order of matrix $=$ Number of rows $x$ Number of columns $=(3 \times 4)$
(iv) Number of entries $=$ (Number of rows) $\times$ (Number of columns)
$=3 \times 4$
$=12$
(V) $a_{i j}=$ element of $i^{t h}$ row and $j^{t h}$ column
$a_{23}=8$
$a_{31}=\sqrt{2}$
$a_{14}=1$
$a_{33}=4$
$a_{22}=0$