1. ## Vectors

I do not know who to do this.

2. ## Re: Vectors

Originally Posted by Stuck Man
I do not know who to do this.
Who? I know: you can do this!

Do you know how to substitute values into a function? Basically, you have a function
$$f(x_1,y_1,x_2,y_2)=x_1y_2-x_2y_1.$$
How do you expand
$$f(x_2,y_2,x_1,y_1)$$
according to the definition above?

3. ## Re: Vectors

Thanks. That was quite unusual.

4. ## Re: Vectors

It was, simply, an exercise in reading and applying a definition. Nothing unusual about that.