The University of Sydney - School of Mathematics and Statistics

Vectors as directed line segments	Page 1 of 4

Vectors are represented in a natural way by directed line segments, the length of the segment measuring the magnitude of the vector and the arrowhead indicating the direction of the vector. The arrowhead is usually placed at one end (or near the end) of the line segment; this end is called the head of the vector and the other end is called the tail of the vector. Such vectors are called free vectors because they are distinguished only by their length and direction, and not by their position in space.

The vector with the same magnitude as u but opposite direction, the negative of u, is labelled -u.

The zero vector (a vector with zero length and no direction) is written 0.