JEE Mains · Maths · STD 12 - 3 and 4 . metrices and determinant
Let \(A\left[\begin{array}{cc}1 & 2 \\ -1 & 4\end{array}\right] .\) If \(A^{-1}=\alpha I+\beta A, \alpha, \beta \in R, I\) is a \(2 \times 2\) identity matrix, then \(4(\alpha-\beta)\) is equal to:
- A \(5\)
- B \(4\)
- C \(2\)
- D \(\frac{8}{3}\)
Answer & Solution
Correct Answer
(B) \(4\)
Step-by-step Solution
Detailed explanation
\(A=\left[\begin{array}{cc}1 & 2 \\ -1 & 4\end{array}\right],|A|=6\)…
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