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Choose the correct answer from the following :
If A is a matrix of order `3xx3" and "|A|=6`, then |adj.A|

A

36

B

216

C

729

D

None of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the determinant of the adjoint of matrix A, given that the determinant of A is |A| = 6 and A is a 3x3 matrix. ### Step-by-Step Solution: 1. **Understand the properties of determinants**: The determinant of the adjoint of a matrix A (denoted as adj A) can be expressed using the formula: \[ | \text{adj} A | = |A|^{n-1} \] where \( n \) is the order of the matrix A. 2. **Identify the order of the matrix**: Since A is a 3x3 matrix, we have: \[ n = 3 \] 3. **Substitute the values into the formula**: Now, we can substitute the values into the formula: \[ | \text{adj} A | = |A|^{3-1} = |A|^2 \] 4. **Use the given determinant of A**: We know that \( |A| = 6 \). Therefore: \[ | \text{adj} A | = 6^2 \] 5. **Calculate the square of the determinant**: Now, calculate \( 6^2 \): \[ | \text{adj} A | = 36 \] 6. **Conclusion**: Thus, the determinant of the adjoint of matrix A is: \[ | \text{adj} A | = 36 \] ### Final Answer: The value of |adj A| is 36.
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