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Let A be a 3xx3 matrix given by A = [a(...

Let A be a `3xx3` matrix given by ` A = [a_(ij)].` If for every
column vector `X, X^(T)AX=O and a_(23)=-1008, ` the sum
of the digits of `a_(32)` is

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The correct Answer is:
To solve the problem, we start by analyzing the given information about the matrix \( A \) and the condition \( X^T A X = 0 \) for every column vector \( X \). ### Step-by-Step Solution: 1. **Understanding the Condition**: The condition \( X^T A X = 0 \) for every vector \( X \) implies that the matrix \( A \) is a skew-symmetric matrix. This means that \( A^T = -A \). 2. **Matrix Representation**: Let \( A \) be represented as: \[ A = \begin{bmatrix} a_{11} & a_{12} & a_{13} \\ a_{21} & a_{22} & a_{23} \\ a_{31} & a_{32} & a_{33} \end{bmatrix} \] 3. **Using the Skew-Symmetric Property**: From the skew-symmetric property, we have: \[ a_{ij} = -a_{ji} \] Therefore, we can write the relationships: - \( a_{21} = -a_{12} \) - \( a_{31} = -a_{13} \) - \( a_{32} = -a_{23} \) - \( a_{33} = 0 \) (since \( a_{33} = -a_{33} \)) 4. **Given Information**: We are given that \( a_{23} = -1008 \). 5. **Finding \( a_{32} \)**: Using the relationship derived from the skew-symmetric property: \[ a_{32} = -a_{23} \] Substituting the value of \( a_{23} \): \[ a_{32} = -(-1008) = 1008 \] 6. **Calculating the Sum of the Digits of \( a_{32} \)**: Now, we need to find the sum of the digits of \( a_{32} = 1008 \). - The digits of \( 1008 \) are \( 1, 0, 0, 8 \). - The sum of these digits is: \[ 1 + 0 + 0 + 8 = 9 \] ### Final Answer: The sum of the digits of \( a_{32} \) is \( 9 \). ---

To solve the problem, we start by analyzing the given information about the matrix \( A \) and the condition \( X^T A X = 0 \) for every column vector \( X \). ### Step-by-Step Solution: 1. **Understanding the Condition**: The condition \( X^T A X = 0 \) for every vector \( X \) implies that the matrix \( A \) is a skew-symmetric matrix. This means that \( A^T = -A \). 2. **Matrix Representation**: ...
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