COMEDK · Maths · 21. Matrices
\(\text { If A }(\operatorname{adj} A)=5 I \text {, where I is the identity matrix of order } 3 \text {, then }|\operatorname{adj} A|=\)
- A 25
- B 10
- C 125
- D 5
Answer & Solution
Correct Answer
(A) 25
Step-by-step Solution
Detailed explanation
Given the property of the adjoint of a matrix, \(A(\operatorname{adj} A) = |A|I\). Comparing this with the given equation \(A(\operatorname{adj} A) = 5I\), we find that \(|A| = 5\). The determinant of the adjoint of a matrix of order \(n\) is given by…
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