Q135 / 200 · TS EAMCET 2002 · Mathematics

If $A=\left[\begin{array}{lll}1 & 0 & 1 \\ 2 & 1 & 0 \\ 3 & 2 & 1\end{array}\right]$, then det $A$ is equal to

  • Correct answer
    A
    $2$
  • B
    $5$
  • C
    $3$
  • D
    $4$

Solution

We have, $$ \begin{aligned} |A| & =\left|\begin{array}{lll} 1 & 0 & 1 \\ 2 & 1 & 0 \\ 3 & 2 & 1 \end{array}\right|=1(1-0)+0+1(4-3) \\ & =1+1=2 \end{aligned} $$

Hence, the correct answer is option: 'A'.

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