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If A=[(b,0,0),(0,b,0),(0,0,b)] then the ...

If `A=[(b,0,0),(0,b,0),(0,0,b)]` then the value of `|A||adjA|` is

A

`b^(3)`

B

`b^(9)`

C

`b^(6)`

D

`b^(8)`

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The correct Answer is:
To solve the problem, we need to find the value of \(|A| \cdot |adj A|\) for the matrix \(A = \begin{pmatrix} b & 0 & 0 \\ 0 & b & 0 \\ 0 & 0 & b \end{pmatrix}\). ### Step-by-step Solution: 1. **Calculate the Determinant of Matrix A**: The determinant of a diagonal matrix is the product of its diagonal elements. Here, the diagonal elements are \(b, b, b\). \[ |A| = b \cdot b \cdot b = b^3 \] 2. **Find the Adjoint of Matrix A**: For any square matrix \(A\), the adjoint (or adjugate) of \(A\) can be calculated using the formula: \[ |adj A| = |A|^{n-1} \] where \(n\) is the order of the matrix. Since \(A\) is a \(3 \times 3\) matrix, \(n = 3\). \[ |adj A| = |A|^{3-1} = |A|^2 = (b^3)^2 = b^6 \] 3. **Calculate the Product of Determinant of A and Determinant of Adjoint A**: Now, we can find \(|A| \cdot |adj A|\): \[ |A| \cdot |adj A| = b^3 \cdot b^6 = b^{3+6} = b^9 \] ### Final Answer: The value of \(|A| \cdot |adj A|\) is \(b^9\). ---

To solve the problem, we need to find the value of \(|A| \cdot |adj A|\) for the matrix \(A = \begin{pmatrix} b & 0 & 0 \\ 0 & b & 0 \\ 0 & 0 & b \end{pmatrix}\). ### Step-by-step Solution: 1. **Calculate the Determinant of Matrix A**: The determinant of a diagonal matrix is the product of its diagonal elements. Here, the diagonal elements are \(b, b, b\). \[ |A| = b \cdot b \cdot b = b^3 ...
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