alleryIf A is orthogonal (A A^T = I), then |A| =
A|A|²
B2
C±1
D0
Answer & Solution
Correct answer: C. ±1
|A A^T| = |I| = 1. But |A A^T| = |A| × |A^T| = |A|².
So |A|² = 1 → |A| = ±1. Det +1: proper rotation.
**Det -1:** improper (rotation × reflection).
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