Question

Determine whether the vectors u and v are parallel, orthogonal, or neither. u = <1, -2>, v = <-4, 8>

Answer 1

two vectors are orthogonal(perpendicular) if their dot-product is 0

so.. let's check that (1*-4) + (-2*8) -> -4-16 -> -20

so, they're not orthogonal

two vectors are parallel if one is the scalar multiplication of the other, namely, they're just multiples of each other

hmm let's see 1, -2, now if we do say -4<1,-2> we end up with < (-4*1) , (-4*-2)> which is < -4 , 8>

thus.. they're parallel then