What is the normal system for $Ax$ when $A$ is orthogonal?
That is the exact wording of the question.
Can anybody help me with this? I'm not sure what they are asking when they say "normal system". Is it referring to a perpendicular system? or just using normal in the layman's terms?
I know if $A$ is orthogonal, then $\Vert Ax\Vert=\Vert x \Vert$.
This is a question from Anton and Rorres in the orthogonal matrices chapter.
Thanks