created 08/26/97; revised 11/11/00, 07/22/03, 07/22/09, 01/10/15

This chapter discusses a second important vector property:
**direction**.
The previous chapter discussed the **length** of a vector.
These are the two properties that define a vector.

- Orientation of 2D vectors (represented in a particular coordinate frame)
- Ambiguity when using arc tan to calculate angle
- Converting length and orientation into components of a column matrix
- Radians and degrees
- C and Java programing with arc tangent

What do you suppose is the direction of the vector represented by:

(4, 0)^{T}