Let A be an n × n invertible matrix. Show that if i ≠ j, then row vector i of A and column vector j of A-1 are orthogonal. I'm lost in regards to where to lost. I want to show that a vector from row vector i from A is orthogonal to a column vector j from A. Orthogonal means the dot product is 0 or the angle between the 2 vectors is 90 degrees. After stating the obvious I'm stuck. I think I need to start with figuring out what the relationship between a row vector from A and a column vector from A^-1 is, but how do I do that?