JackInTheBox

cos 90 = 0 (orthogonal vectors have 90 in between) substitute a vector [x1 , x2, x3] for the second vector and use dot product [3, -1, 4] . [x1, x2, x3] = 0 3x1 - x2 + 4x3 = 0 then solve for xs that would work. an example would be [1, 3, 0]