Question

The rank of the matrix $A=\left\{\begin{array}{ccc}1& 1& 1\\ 1& 1& 1\\ 1& 1& 1\end{array}\right\}is$

• A. $3$
• B. $2$
• C. $1$
• D. $0$

Answer 1

Answer: (C)

$1$

The determinant of matrix $A_{3\times 3}$ is 0
Now, take any $2\times 2$ matrix and calculating its determinant value its also comes out to be 0
And if we take single element of A we found that it is non-zero
$\therefore$ Rank of given matrix $=1$