ExamBro
ExamBro
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

  1. A 10
  2. B 100
  3. C 1000
  4. D 10000
Verified Solution

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 \(A\)…