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If 

where x,y,z are integers, is an orthogonal matrix, then what is A2 equal to?

This question was previously asked in
NDA-I (Mathematics) Official Paper (Held On: 13 Apr, 2025)
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  1. Null matrix 
  2. Identity matrix
  3. A
  4. -A

Answer (Detailed Solution Below)

Option 2 : Identity matrix
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Detailed Solution

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Calculation:

Given,

Matrix A is defined as:

It is mentioned that A is an orthogonal matrix. Therefore,

Now, we calculate A2:

Since A is orthogonal, , and hence:

∴ A2 = Identity matrix (I).

Hence, the Correct answer is Option 2.

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