Recent content by cptcook

again, i cannot calculate the cross product of two arbitrary vectors in r3. it becomes a giant vector equation which is non-arrangeable. cross product seems like a dead end.

even if i don't use triple scalar product and do what you suggest, i'd still have to calculate cross product (which i know how to do it), correct me if I'm wrong but; u X v= det |(i,j,k),(u1,u2,u3),(v1,v2,v3)| right? that gives you a gigantic equation of nothing when calculated, which cannot be...

That is the general idea, yes but still, how to calculate n=u X v when i do not even have numbers, i think I'm missing your point here, can you be just a little more specific? i tried defining the vectors as u=(u1,u2,u3) and v=(v1,v2,v3) and then calculating the triple scalar product. it got me...

ok i already went down that road and got lost, if i had numbers, it would be easier but how can i prove that they are coplanar if all i have is arbitrary vectors?

Homework Statement Let s and t be scalars. show that u, v and su + tv are coplanar. u and v are arbitrary vectors, Homework EquationsThe Attempt at a Solution Well, i suppose if they are coplanar, triple scalar product of them should be 0, right? and su+tv is evidently a linear combination of...