Question

Is this identity matrix?

[ 0 0 1 ]
[ 0 1 0 ]
[ 1 0 0 ]

???

Answer 1

Close; just flip the matrix. The 1's are on the main-diagonal.

[ 1 0 0 ]
[ 0 1 0 ]
[ 0 0 1 ]

Answer 2

ok thanks

Answer 3

what is it good for?

Answer 4

It satisfies the law of identity for matrix like:
A*I = A
or A*A^-1 = I
where I is identity matrix and A is any other matrix of same order

Answer 5

ok i get it, thanx!