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If A is a square matrix of order 3 such ...

If A is a square matrix of order 3 such that `abs(A)=2,` then
`abs((adjA^(-1))^(-1))` is

A

1

B

2

C

4

D

8

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the value of \( \text{abs}((\text{adj} A^{-1})^{-1}) \) given that \( \text{abs}(A) = 2 \) and \( A \) is a square matrix of order 3. ### Step-by-step Solution: 1. **Understanding the Problem**: We know that \( A \) is a square matrix of order 3, which means \( n = 3 \). We are given that \( \text{abs}(A) = 2 \). 2. **Using the Properties of Determinants**: We need to find \( \text{abs}((\text{adj} A^{-1})^{-1}) \). We can use the property of determinants: \[ \text{abs}(A^{-1}) = \frac{1}{\text{abs}(A)} \] Therefore, \[ \text{abs}(A^{-1}) = \frac{1}{2} \] 3. **Finding the Determinant of the Adjoint**: The determinant of the adjoint of a matrix \( A \) is given by: \[ \text{abs}(\text{adj} A) = \text{abs}(A)^{n-1} \] For our matrix \( A \) of order 3, this becomes: \[ \text{abs}(\text{adj} A) = \text{abs}(A)^{3-1} = \text{abs}(A)^2 = 2^2 = 4 \] 4. **Finding the Determinant of the Adjoint of the Inverse**: Now, we need to find \( \text{abs}(\text{adj} A^{-1}) \). Using the property of the adjoint: \[ \text{abs}(\text{adj} A^{-1}) = \text{abs}(A^{-1})^{n-1} \] Substituting \( \text{abs}(A^{-1}) = \frac{1}{2} \): \[ \text{abs}(\text{adj} A^{-1}) = \left(\frac{1}{2}\right)^{3-1} = \left(\frac{1}{2}\right)^2 = \frac{1}{4} \] 5. **Finding the Determinant of the Inverse of the Adjoint**: We now need \( \text{abs}((\text{adj} A^{-1})^{-1}) \): \[ \text{abs}((\text{adj} A^{-1})^{-1}) = \frac{1}{\text{abs}(\text{adj} A^{-1})} \] Substituting \( \text{abs}(\text{adj} A^{-1}) = \frac{1}{4} \): \[ \text{abs}((\text{adj} A^{-1})^{-1}) = \frac{1}{\frac{1}{4}} = 4 \] ### Final Answer: Thus, the value of \( \text{abs}((\text{adj} A^{-1})^{-1}) \) is \( 4 \).

To solve the problem, we need to find the value of \( \text{abs}((\text{adj} A^{-1})^{-1}) \) given that \( \text{abs}(A) = 2 \) and \( A \) is a square matrix of order 3. ### Step-by-step Solution: 1. **Understanding the Problem**: We know that \( A \) is a square matrix of order 3, which means \( n = 3 \). We are given that \( \text{abs}(A) = 2 \). 2. **Using the Properties of Determinants**: ...
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