sorry to start another thread on this but i still don't get it!!
the question: solve y+(axy)=b (where x represents cross product) for x in terms of a and b.
what i did is as follows...
i took the cros product of each side with a:
why is this wrong and what is the right way? I have been told i should take dot product and scalar product of both sides, but i dont see how this helps.
Turn on thread page Beta
- Thread Starter
- 15-11-2005 22:56
(Original post by realicetic)
- 15-11-2005 23:18
axy = n|a||y|sinØ. Since a is perpendicular to n,then axn = |a|²|n||y|k roughly(K perp to n and a(is this y?)), which is not the same as axy.
I havent done dot and cross in a while, but I suspect that you can do this:
dot a to everything, then you obtain
a.y+ a.(axy) = a.b
Since a.y will produce a perpendicular vector to a, a.(axy) = 0. (as the angle between then is now 90°, cos 90 = 0).
Hence a.y = a.b.
You can do the rest if you can go further, cause my memory just ran out