"|" probably means nothing.
"|A|", on the other hand, would mean the magnitude of a vector "A".
"x" indicates a Cross Product.
I want to calculate the radius of a circle given three points on its perimeter. So I find this formula:
Circle - Wikipedia, the free encyclopedia
|P1-P2| |P2-P3| |P3-P1|
------------------------- = r
2 |(P1-P2)x(P2-P3)|
where the P's are 1 by 3 vectors with x,y,z coordinates of the points 1,2,3.
What does the "|" mean in the matrix world? Isn't that the length of the vector in geometry?
And the "x" oepration? Is that matrix multiplication? Then how could that be performed on two 1 by 3 vectors???
Thankful for clarification!