JEE Mains · Maths · STD 12 - 3 and 4 . metrices and determinant
If the matrix \(A=\left(\begin{array}{cc}0 & 2 \\ K & -1\end{array}\right)\) satisfies \(A\left(A^{3}+3 I\right)=2 I\) then the value of \(\mathrm{K}\) is :
- A \(\frac{1}{2}\)
- B \(-\frac{1}{2}\)
- C \(-1\)
- D \(1\)
Answer & Solution
Correct Answer
(A) \(\frac{1}{2}\)
Step-by-step Solution
Detailed explanation
Given matrix \(A=\left[\begin{array}{cc}0 & 2 \\ k & -1\end{array}\right]\) \(A^{4}+3 I A=2 I\) \(\Rightarrow A^{4}=2 I-3 A\) Also characteristic equation of \(\mathrm{A}\) is \(|\mathrm{A}-\lambda \mathrm{I}|=0\)…
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