maths help please

Going to Cali · 13 May 2008 at 13:27

[0,0,1,0]
[0,1,0,0]
[0,0,-1,0]

=

[0,-1,0,0]

I can't figure out how these can multiply together to yield the result. Any ideas?

Duff-Man · 13 May 2008 at 13:44

err: (the first one) + (the last one) - (the centre one)?

Couldn't get much simpler, to be honest.

Going to Cali · 13 May 2008 at 13:51

How does that work for;

[0,-1,0,0]
[0,1,0,0]
[0,1,0,1]

=

[0,1,0,0]

?

Ben M · 13 May 2008 at 14:09

do your own homework

OSB · 13 May 2008 at 14:11

What have you actually got to do? Create the last one from the first three? And what actually are they? Vectors?

Fyebot · 13 May 2008 at 16:39

I suspect it's using the cross product? (writen as u x v where u,v are vectors)

Otherwise might be a mix of cross and dot product (dot product is often written as u.v or just uv if it's like that in the question?)

Edit: Uh, maybe not actually .. cross products only for 3 element vectors, have a look through your notes and it should have defined what they mean by "multiply" for vectors somewhere. Could also be matrix multiplication but I don't think that'd give the right answer.

Aero · 13 May 2008 at 19:11

Looks like a matrix to me but its been a couple of years since i did them.

Aero

Vixen · 13 May 2008 at 19:37

Going to Cali said:
How does that work for;

[0,-1,0,0]
[0,1,0,0]
[0,1,0,1]

=

[0,1,0,0]

?

If you've been given that as homework, then you must have been told how to multiply matrices.