|Vectors can be used to represent quantities that involve both direction and magnitude. There are also quantities whic have magnitude but not direction. These quantities are called scalars.|
In the above figure we have three parallel straight lines and there are two different directions that can be associated with these lines as shown by arrowheads. A line with one of these directions prescribed is called a directed line. If a magnitude , say a units in the form of line segment on this line together with one of the two directions on the line are prescribed, we say that we have a directed line segment . In the third line, AB, A is called the initial point and B is called the terminal point of the directed line segment.Since the directed line segment has both magnitude and direction, we call it a vector. Magnitude of a vector is written as |->|
a We employ the symbol AB with a ray symbol above it or a with a ray symbol above to denote the vector.
Types of vectors
Example: Find the magnitude of | 3i + 2 j +4 k|
Directions: Answer the following.