Expert: Scott A Wilson - 1/14/2011

Question
What is the use of finding dot and cross product of vectors? I don't know why we are finding. What result these 2 operations are telling? Please explain me.

Answer
For the dot product between two vectors, they come out to follow
v · w = ||v|| ||w|| cos(A), where A is the angle between the two vectors.
If the dot product is 0, the vectors are perpendicular.

For cross products, they come out to follow
||v × w|| = ||v|| ||w|| sin(A), where A is the angle between the two vectors.
The cross product will give you the area of the parllelogram defined by two vectors.