If A is 4 x 4 and orthogonal. then the inner product of any two different columns of A
Chapter 0, Problem 15(choose chapter or problem)
If A is 4 x 4 and orthogonal. then the inner product of any two different columns of A is zero.
Unfortunately, we don't have that question answered yet. But you can get it answered in just 5 hours by Logging in or Becoming a subscriber.
Becoming a subscriber
Or look for another answer