JEE Mains · Maths · STD 12 - 3 and 4 . metrices and determinant
Let \(A\) be a \(2 \times 2\) real matrix with entries from \(\{0,1\}\) and \(|\mathrm{A}| \neq 0 .\) Consider the following two statements : \((P)\) If \(A \neq I_{2},\) then \(|A|=-1\) \((\mathrm{Q})\) If \(|\mathrm{A}|=1,\) then \(\operatorname{tr}(\mathrm{A})=2\) where \(I_{2}\) denotes \(2 \times 2\) identity matrix and \(\operatorname{tr}(A)\) denotes the sum of the diagonal entries of \(A\) Then
- A \((P)\) is true and \((\mathrm{Q})\) is false
- B Both \((P)\) and \((Q)\) are false
- C Both \((P)\) and \((Q)\) are true
- D \((P)\) is false and \((Q)\) is true
Answer & Solution
Correct Answer
(D) \((P)\) is false and \((Q)\) is true
Step-by-step Solution
Detailed explanation
\(|A| \neq 0\) For \((\mathrm{P}): \mathrm{A} \neq \mathrm{I}_{2}\) So, \(A=\left[\begin{array}{ll}0 & 1 \\ 1 & 0\end{array}\right]\) or \(\left[\begin{array}{ll}1 & 1 \\ 1 & 0\end{array}\right]\) or \(\left[\begin{array}{ll}0 & 1 \\ 1 & 1\end{array}\right]\) or…
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