COMEDK · Maths · 21. Matrices
If \(A\) is a matrix of order \(4 \operatorname{such}\) that \(A(\operatorname{adj} A)\) \(=10 \mathrm{I}\), then \(|\operatorname{adj} A|\) is equal to
- A 10
- B 100
- C 1000
- D 10000
Answer & Solution
Correct Answer
(C) 1000
Step-by-step Solution
Detailed explanation
Given, \(A(\operatorname{adj} A)=10 I\) We know that \(A(\operatorname{adj} A)=|A| I\) \(\begin{array}{ll} \therefore & 10 I=|A| I \\ \Rightarrow & |A|=10 \end{array}\) We know that \(|\operatorname{adj} A|=|A|^{n-1}\), where \(n\) is order of \(A\)…
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