If is any invertible matrix, then there must exist two perpendicular unit vectors and such that the vectors and are perpendicular as well.
Bonus Question : Can you generalize to 3 or even dimensions?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Let A be any n × n invertible matrix. So, without any loss of generalization, we can suppose that A is the matrix representation of any bijective Linear Transformation T : X → Y , where the dimension of both, X and Y is n , which are both Vector Spaces. As vector space it is, there exist n linearly independent vectors in Y which are its Basis. By Gram-Schmidt's process, there is an orthonormal set of vectors which are basis of Y and other set of vectors for X . And then is clear that, because of the bijectivity of T there are n vectors v 1 , v 2 , . . . v n ∈ X such that A v 1 ⊥ A v 2 ⊥ . . . ⊥ A v n