Co planar?

[Elnino_Gerrard]

So i have 2 vectors a and b all i have to do is prove a=kb  for co planar?
How about 3 vectors?

[98.40_for_sure]

Isn't... coplanar mean same plane? a=kb is proving that they are parallel

[jasoN-]

what's co planar? is it co linear?
if it is colinear, then for example you had 3 position vectors OA, OB, OC
need to show that AB = kBC
and that both vectors share a common point (ie. B for the above example)

[Elnino_Gerrard]

Yea my bad i think i meant co- linear

[Elnino_Gerrard]

what's co planar? is it co linear?
if it is colinear, then for example you had 3 position vectors OA, OB, OC
need to show that AB = kBC
and that both vectors share a common point (ie. B for the above example)

Yep thats the answer i was looking for thanks mate

[itolduso]

how do you show a=2i-3j+k, b=5i-5j and c=i+j-2k are coplanar?

[medge]

how do you show a=2i-3j+k, b=5i-5j and c=i+j-2k are coplanar?

If three vectors , and are coplanar, and , then

    (,

where denotes the unit vector in the direction of .

Or, the vector resolutes of on and on add to give the original .

^ according to wikipedia. I don't recall that being part of the course though...

[TrueTears]

So i have 2 vectors a and b all i have to do is prove a=kb  for co planar?
How about 3 vectors?

um this isn't in the spesh course... at least i hope not, if anyone is interested.

if 2 vectors, a and b, are coplanar then a x b = 0.

if their cross product is = 0 then that means they MUST lie in the same plane, or else they will get a orthogonal vector that is not 0

[itolduso]

cross product is not in spesh

[TrueTears]

thought so, i wonder why he/she asked this q lol

[itolduso]

So i have 2 vectors a and b all i have to do is prove a=kb  for co planar?
How about 3 vectors?

Any two vectors with a common point are always coplanar. You dont have to show it.
Three vectors are coplanar if they are linearly dependent and have a common point. No cross product is necessary.