Solveeit Logo
Login

Question

Question: If A = \(\begin{bmatrix} 1 & 2 & - 1 \\ - 1 & 1 & 2 \\ 2 & - 1 & 1 \end{bmatrix}\) then determinant ...

If A = [12−1−1122−11]\begin{bmatrix} 1 & 2 & - 1 \\ - 1 & 1 & 2 \\ 2 & - 1 & 1 \end{bmatrix} then determinant (Adj (Adj A)) is –

A

(14)⁴

B

(14)³

C

(14)²

D

(14)¹

Answer

(14)⁴

Explanation

Solution

|A| = $\left| \begin{matrix} 1 & 2 & - 1 \

  • 1 & 1 & 2 \ 2 & - 1 & 1 \end{matrix} \right|$= 14

\ |Adj. (Adj A)| = ∣A∣(n−1)2|A|^{(n - 1)^{2}}

= 142214^{2^{2}}= (14)4