I have the three building vectors of two different parallelepipeds.
P = e1, e2, e3
G = ae3+e1, be3+e2, e3
I have to prove that
|(e1Xe2).e3| = |((ae3+e1)X(be3+e2)).e3|
where X vector product and
. scalar product
thanks.
see this :Volume of a Parallelepiped - YouTube