Vector cross product

[Cpt Qwark]

Homework Statement

Given a×b=-i-j+3k and c×a=2i-3j+k, find a×(a-2b+c)

Homework Equations

Cross product (DONE WITHOUT MATRICES).

The Attempt at a Solution

a[/B]×b=c=-(b×a)is all I'm getting to at this point

 

[SammyS]

Homework Statement

Given a×b=-i-j+3k and c×a=2i-3j+k, find a×(a-2b+c)

Homework Equations

Cross product (DONE WITHOUT MATRICES).

The Attempt at a Solution

a[/B]×b=c=-(b×a)is all I'm getting to at this point

Simply distribute the cross-product.

$\vec{P}\times(\vec{Q}+\vec{R})=\vec{P}\times\vec{Q}+\vec{P}\times\vec{R}$

 

[Cpt Qwark]

Thanks,
so would I have to find the components of a, b, and c?

 

[SammyS]

Thanks,
so would I have to find the components of a, b, and c?

No. Not at all.

What is a×a ?

 

[Dick]

Thanks,
so would I have to find the components of a, b, and c?

No, you only need the components of axb and axc. Follow SammyS's suggestion.

 

[Cpt Qwark]

Ok thanks guys I got it