Question

Determine whether the vectors u and v are parallel, orthogonal, or neither. u = <10, 0>, v = <0, -9>

Answer 1

Two vectors are orthogonal (perpendicular), if their dot-product is zero
they're parallel, if they're just the product of scalar multiplication

like say hmmm <3, 7>  and <12, 28>   well 4*3 is 12, and 4*7 is 28
thus <12, 28> is really 4<3,7>  so, those two are parallel

now.. let's check the dot-product on yours

<10, 0> • <0,-9>   will be (10*0) + (0*-9) = 0 + 0 = 0 <--- orthogonal