What does it means if subspaces to be orthogonal?
First of all what does it means if 2 vectors are to be orthogonal?
Give me a Y vector which is orthogonal to a vector X [1 2 3]:
Ans: Rule is X(Transponse) dot Y = [0; 0; 0]
so, once possible Y vector is [3; 0; -1;]

What does it means if subspaces to be orthogonal?

First of all what does it means if 2 vectors are to be orthogonal?

Give me a Y vector which is orthogonal to a vector X \[1 2 3\]:

Ans: Rule is X(Transponse) dot Y = \[0; 0; 0\]

so, once possible Y vector is \[3; 0; -1;\]

Some notes on Subspaces