# Math Help - question about rotation matrix

1. ## question about rotation matrix

not sure about part 1 of question and......

Really unfamiliar with rotation matrix( including reflection, orthogonal matrix)

can anyone also tell me the connection between them, and some important properties of them???

Thanks very much!!!

2. Hello,

To prove that a matrix is a rotation matrix, you have to check :
- vectors are norm 1 (lines or columns, it's not important)
- determinant > 0 (since vectors are norm 1, it automatically implies that the determinant is =1)

The axis will be the eigenspace generated by 1 (I'm not sure if there are further things to do here) :

$AX=X$

It's like in geometry : the axis doesn't change when rotating.