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Question

Question: If A is an orthogonal matrix, then \|A\| is-...

If A is an orthogonal matrix, then |A| is-

A

1

B

–1

C

± 1

D

0

Answer

± 1

Explanation

Solution

As A is an orthogonal matrix,

A¢A = AA¢ = In

Ž |A¢A| = |AA¢| = |In|

Ž |A¢| |A| = 1

Ž |A| |A| = 1

Ž |A|2 = 1 Ž |A| = ± 1