Let A be a 3 × 3 square matrix, such that A (adj A) = 2I, where I… - Vidyadip

Question

Let A be a 3 × 3 square matrix, such that A (adj A) = 2I, where I is the identity matrix. Write the value of |adj A|.

✓

Answer

$\because$ A(adj (A)) = |A|I

2I = |A|I (Given A(adj A) = 2I)

|A| = 2

Also, |adj A| = |A|^n-1

= (2)^3-1

= (2)²

= 4

|adj A| = 4

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