Question
Which of the following matrices are singular or non-singular?

$\left[\begin{array}{ccc}\mathbf{a} & \mathbf{b} & \mathbf{c} \\ \mathbf{p} & \mathbf{q} & \mathbf{r} \\ \mathbf{2 a - p} & \mathbf{2 b}-\mathbf{q} & \mathbf{2 c}-\mathbf{r}\end{array}\right]$

Answer

Let $A=\left[\begin{array}{ccc}a & b & c \\ p & q & r \\ 2 a-p & 2 b-q & 2 c-r\end{array}\right]$

$\therefore \quad|A|=\left|\begin{array}{ccc}a & b & c \\ p & q & r \\ 2 a-p & 2 b-q & 2 c-r\end{array}\right|$

Applying $R_3 \rightarrow R_3+R_2$, wé get$|A|=\left|\begin{array}{ccc}a & b & c \\ p & q & r \\ 2 a & 2 b & 2 c\end{array}\right|$

Taking 2 common from $R_3$, we get

$|A|=2\left|\begin{array}{lll}a & b & c \\ p & q & r \\ a & b & c\end{array}\right|$

$=2(0) \quad \ldots\left[\because R_1\right.$ and $R_3$ are identical $]$

$=0$

$\therefore \quad$ A is a singular matrix.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free