Question: how to show that two vectors are perpendicular to each other?
Answer: Two vectors u = (a,b) and v = (c,d) in a coordinate plane are perpendicular if and only if their scalar product a*c + b*d is equal to zero: a*c + b*d = 0. ) are perpendicular. = 3 - 3 = 0. Since the scalar of the vectors u and v is zero, these vectors are perpendicular.