Thread: How to prove: A,B are orthogonal matrices, if det(A)+det(B)=0, then A+B is singular.

Thanks a lot!!!

Originally Posted by seekor

Thanks a lot!!!

Where is the question? seekor, please don't delete posts once you have the answer. Someone else might be able to benefit from them as well.

-Dan

Originally Posted by topsquark

The other thread has been locked. The question is:


If then


Thus the matrix A + B is singular because it has a zero determinant.

-Dan

In general,

Example:

For square matrices,

Originally Posted by JakeD

In general,

Example:

For square matrices,

(sigh) I thought there was something fishy going on there. I guess I was tired last night! Thanks for the spot.

-Dan