Vectors and properties of cross products

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• Sep 19th 2013, 03:25 PM
Shadow236
Vectors and properties of cross products
The problem that I am unsure about is: k x (i - 2j). What are the rules for adding and subtracting vectors like this?
• Sep 19th 2013, 04:06 PM
Plato
Re: Vectors and properties of cross products
Quote:

Originally Posted by Shadow236
The problem that I am unsure about is: K x (i - 2j). What are the rules for adding and subtracting vectors like this?

Be careful about notation, in particular capitalization.
I think you mean: $k\times(i-2j)~?$

The rules are: $\vec{a}\times(\vec{b}+\vec{c})=(\vec{a}\times\vec{ b})+(\vec{a}\times\vec{c})$ and $(\alpha\vec{ a}\times\vec{b})=\alpha(\vec{a}\times\vec{b})$
• Sep 19th 2013, 04:09 PM
Shadow236
Re: Vectors and properties of cross products
Okay, I fixed it.

In that case I went through the problem like this...

= k x i + (-2)(k x j)
= j - 2i