JEE Mains · Maths · STD 12 - 3 and 4 . metrices and determinant
Let \(A =\left[\begin{array}{ll} a & b \\ c & d \end{array}\right]\) and \(B =\left[\begin{array}{l}\alpha \\ \beta\end{array}\right] \neq\left[\begin{array}{l}0 \\ 0\end{array}\right]\) such that
\(AB = B\) and \(a + d =2021,\) then the value of \(ad - bc\) is equal to ...... .
- A \(1010\)
- B \(1560\)
- C \(2250\)
- D \(2020\)
Answer & Solution
Correct Answer
(D) \(2020\)
Step-by-step Solution
Detailed explanation
\(A =\left[\begin{array}{ll} a & b \\ c & d \end{array}\right], B =\left[\begin{array}{l}\alpha \\ \beta\end{array}\right]\) \(AB = B\) \(\Rightarrow( A - I ) B = O\) \(\Rightarrow| A - I |= O ,\) since \(B \neq O\)…
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