ABSTRACT
The word ‘vector’ means carrier in Latin and what a vector carries is information about length and direction, and nothing else. Because vectors stay the same when they move parallel to themselves, they also preserve information about angles. Parametric equations generate points that belong to a geometric object by varying the value or values of a parameter or parameters. Non-parametric equations are used to check whether a point belongs or does not belong to a geometric object. They are essentially relations. A scalar is just a number and has magnitude but no direction. A vector has magnitude and direction. These are represented by directed line segments. The corresponding equivalence relation is defined on the set of all directed line segments and says that two such segments are related if they are parallel, point in the same direction and have the same length. It amounts to the same thing to regard a vector as being a directed line segment.
