Matrix multiplication identity

For multiplication of any matrix, the identity matrix is:

For a 2x2 identity matrix, it is:

Proof for a 2x2 identity matrix

Let and , then:

• Similarly, going the other way round:

Proof for a 3x3 identity matrix

This is the same thing, but not quite so neat to write out…

Let and , then:

• Similarly, going the other way round: