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JEE Mains · Maths · STD 12 - 3 and 4 . metrices and determinant

माना \(B=\left[\begin{array}{lll}1 & 3 & \alpha \\ 1 & 2 & 3 \\ \alpha & \alpha & 4\end{array}\right], \alpha>2\), एक आव्यूह \(A\) का सहखंडज है तथा \(|\mathrm{A}|=2\) है। तो \([\alpha-2 \alpha \alpha] \mathrm{B}\left[\begin{array}{c}\alpha \\ -2 \alpha \\ \alpha\end{array}\right]\) बराबर है :-

  1. A \(16\)
  2. B \(32\)
  3. C \(-16\)
  4. D \(0\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(-16\)

Step-by-step Solution

Detailed explanation

Given, \(B=\left[\begin{array}{lll}1 & 3 & \alpha \\ 1 & 2 & 3 \\ \alpha & \alpha & 4\end{array}\right]\) \(|B|=4\) \(1(8-3 \alpha)-3(4-3 \alpha)+\alpha(\alpha-2 \alpha)=4\) \(-\alpha^2+6 \alpha-8=0\) \(\alpha=2,4\) Given,\(\alpha > 2\) So,\(\alpha=2\) is rejected…
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