When to use dot product and cross product?
a very big question the small everyday answer for vectors A,B the dot product is a constant and exists for all types of vectors for any two of the same dimension, A*B = |A||B| cos (theta the lesser angle between the vectors) the cartesian formula for the dot product of two three dimensional vectors (A1,A2,A3) (B1,B2,B3) A1B2+A2B2+A3B3 for two n dimensional vectors it is A1B1 + A2B2 + A3B3 + A4B4 … +AnBn the cross product exists for vectors in three dimensional space only it, AXB provides the vector perpendicular to A and B for which |AXB| = |A||B| sin(theta) the lesser angle between the vectors the cartesian formula for vectors a,b is a × b = (a2b3 − a3b2) i + (a3b1 − a1b3) j + (a1b2 − a2b1) k = (a2b3 − a3b2, a3b1 − a1b3, a1b2 − a2b1).
