Question:medium

If $A \cdot \mathrm{adj}(A) = O$, then $|A|$ is}

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$A \cdot \mathrm{adj}(A) = |A|\,I$. If this product is the zero matrix, then $|A| = 0$, i.e.\ $A$ is singular.
Updated On: May 2, 2026
  • 0
  • $\dfrac{1}{|\mathrm{adj}\,A|}$
  • 1
  • $-1$
Show Solution

The Correct Option is A

Solution and Explanation

Step 1: Conceptual Understanding:
Use the standard identity $A \cdot \mathrm{adj}(A) = |A|\,I$.
Step 2: Explanation in Detail:
$A \cdot \mathrm{adj}(A) = |A|\,I = O \Rightarrow |A| = 0$.
Step 3: Therefore, Stating the Final Answer
$|A| = 0$.
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