One fairly standard definition of the dot product of u and v is where is the angle between the vectors. Have you not seen that before?
The dot vector http://www.mathsisfun.com/algebra/ve...t-product.html
This is the geometric dot vector because the definition has cos theta in it:
This is the algebraic dot vector, Let vector a=(x,y,z) b = (m,n,o) :
Also you should note that the dot vector of any two vectors produces a SCALAR.
So provided the information and equation, can you solve the problem you have?