## While multiplying 2 vectors how do I know if I should use dot product or cross product?

01-Dec-2015 3:04 PM
~2

1

It actually depends on the situation you want to use the multiplication. For some applications, dot product is used, while for others cross product is useful.

The dot product gives a scalar number, while a cross product gives us a vector only.

For example, to find the angle between two vectors, you can use cross product easily to find: cos$\theta$ = $\bar{A} . \bar{B}$ / |A||B|

While to find the vector perpendicular to the plane of the 2 vectors, or to calculate torque,it is given by its cross product only.

01-12-2015 17:47
~32