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If `A` is a square matrix such that `A(adjA)=[(4,0,0),(0,4,0),(0,0,4)],` then `=(|adj(adjA)|)/(2|adjA|)` is equal to

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To solve the problem step-by-step, we will follow the reasoning presented in the video transcript. ### Step 1: Understand the given information We are given that: \[ A \cdot \text{adj}(A) = \begin{pmatrix} 4 & 0 & 0 \\ 0 & 4 & 0 \\ 0 & 0 & 4 \end{pmatrix} \] This matrix can be factored as: \[ A \cdot \text{adj}(A) = 4I \] where \( I \) is the identity matrix. ### Step 2: Use the property of determinants From the property of determinants, we know: \[ A \cdot \text{adj}(A) = \det(A) \cdot I \] By comparing this with the previous step, we can conclude: \[ \det(A) = 4 \] ### Step 3: Find the determinant of adjoint of A Using the formula for the determinant of the adjoint of a matrix: \[ \det(\text{adj}(A)) = \det(A)^{n-1} \] where \( n \) is the order of the matrix \( A \). Since \( A \) is a \( 3 \times 3 \) matrix, \( n = 3 \): \[ \det(\text{adj}(A)) = \det(A)^{3-1} = \det(A)^2 = 4^2 = 16 \] ### Step 4: Find the determinant of adjoint of adjoint of A Now, we need to find \( \det(\text{adj}(\text{adj}(A))) \). Using the same property: \[ \det(\text{adj}(B)) = \det(B)^{m-1} \] where \( m \) is the order of the matrix \( B \). Here, \( B = \text{adj}(A) \), which is also a \( 3 \times 3 \) matrix. Therefore: \[ \det(\text{adj}(\text{adj}(A))) = \det(\text{adj}(A))^{3-1} = \det(\text{adj}(A))^2 = 16^2 = 256 \] ### Step 5: Calculate the final expression We need to find: \[ \frac{\det(\text{adj}(\text{adj}(A)))}{2 \cdot \det(\text{adj}(A))} \] Substituting the values we found: \[ \frac{256}{2 \cdot 16} = \frac{256}{32} = 8 \] ### Final Answer Thus, the value is: \[ \boxed{8} \]

To solve the problem step-by-step, we will follow the reasoning presented in the video transcript. ### Step 1: Understand the given information We are given that: \[ A \cdot \text{adj}(A) = \begin{pmatrix} 4 & 0 & 0 \\ 0 & 4 & 0 \\ 0 & 0 & 4 \end{pmatrix} \] This matrix can be factored as: \[ A \cdot \text{adj}(A) = 4I \] where \( I \) is the identity matrix. ...
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