Position Vector

There is one presentation of a vector that is unique in some way.  The presentation of the ¯v = (a₁,a₂,a₃) that begins at the point  A = (0,0,0) and ends at the point B = (a₁,a₂,a₃) is termed as the position vector of the point (a₁,a₂,a₃) . Thus, while we talk about position vectors we are specifying the initial and last point of the vector.  

 Position vectors are helpful if we ever need to present a point as a vector.  As we'll observe there are times where we definitely are going to wish to represent points as vectors.  Actually, we're going to run into topics that can only be done if we present points like vectors.