1. The problem statement, all variables and given/known data Let A be a vector perpendicular to every vector X. Show that A = O Edit: it is O not 0. (OH not zero) ha 2. Relevant equations So, we know if A and X are perpendicular then A(dot)X = 0 I see no reason why A would have to be equal to 0. Could X (not equal) 0? Could it be both? 3. The attempt at a solution Above is my attempt. I get a hint please?