Question

A square matrix is an orthogonal matrix, if

• A. $A{A}^{\prime }=O$
• B. $A+A^{\prime }=I$
• C. $A{A}^{\prime }=I$
• D. None of these

Answer 1

Answer: (C)

$A{A}^{\prime }=I$

Consider a matrix A of $3\times 3$ order.

Now,

$A^{{}^{\prime }}$ is the transpose matrix of matrix $A$.

We know that,If,

$A.A^{{}^{\prime }}=I$

Then , matrix A is orthogonal matrix.

Hence, this is the answer.