i think i may be over complicating this but how do i verify that
5i+3k is parallel to -3i+5k ?
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- Thread Starter
- 13-06-2005 18:14
- 13-06-2005 18:20
Two vectors are parallel when one of them is ai+bj+ck and the other λ(ai+bj+ck)
where λ is a real number
- 13-06-2005 18:28
Wow I've never understood that!! Thanks.
- 13-06-2005 18:33
Isn't it using the dot product?
Cos θ = (a.b)/|a||b|
Where a.b = (ni x mi) + (nj x mj) + (nk x mk)
Since a.b = (5x3)+(-3x5) = 0
θ= arccos 0
θ= 90° ????
- 13-06-2005 18:35
yeh thats correct theyre perpendicular to each other u can tell by looking at the cross product whcih is =0
or vectors [a b] and [-b a] are perp..