Which one of the following matrices is an elementary matrix ?

Where are elementary on a matrix.

If the product of two matries is a zero matrix, it is not necessary that one of the matrices is a zero matrix.

Show that If the product of two matrices is a zero matrix, it is not necessary that one of the matrices is a zero matrix.

If M and N are orthogonal matrices of order 3, then which of the following is (are) orthogonal matrix?

If M and N are orthogonal matrices of order 3, then which of the following is (are) orthogonal matrix?

If M and N are orthogonal matrices of order 3, then which of the following is (are) orthogonal matrix?

If a symmetric /skew symmetric matrix is expressed as a sum of a symmetric and a skew symmetric matrix then prove that one of the matrices in the sum must be zero matrix .