Matrices & Determinants
Adjoint
Grade 12
Question:
<p>If \(A\) is a \(2 \times 2\) matrix and \det(A) = 5, then \det(adj(adj \(A)) is:</p>
<p>(A) 5</p>
<p>(B) 25</p>
<p>(C) 1</p>
<p>(D) 0</p>
Step-by-Step Solution
Key Concept: For 2 \times 2, $\text{adj}(\text{adj } $A)$ = $A$, so determinant remains same.
1. adj(adj $A) = $A$ for $2 \times 2$
2. det remains 5
Correct Answer: 1