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TS EAMCET · Maths · Matrices

If \(A=\left[\begin{array}{lll}1 & 2 & 2 \\ 2 & 1 & 1 \\ 1 & 2 & 1\end{array}\right]\), then \(\left|\operatorname{Adj}\left(A^2\right)\right|=\)

  1. A \(9\)
  2. B \(27\)
  3. C \(729\)
  4. D \(81\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(81\)

Step-by-step Solution

Detailed explanation

\( |A| = 1(1 \cdot 1 - 1 \cdot 2) - 2(2 \cdot 1 - 1 \cdot 1) + 2(2 \cdot 2 - 1 \cdot 1) \) \( |A| = 1(-1) - 2(1) + 2(3) = 3 \) \( \left|\operatorname{Adj}\left(A^2\right)\right| = \left|A^2\right|^{3-1} \)…