**Unit Vector.** Any vector **A** can be represented by the magnitude of the vector |**A**| multiplied by its unit vector written as **a**_{n}

So **A** = |**A**|** a**_{n}.

A unit vector has the direction of the main vector is of unit magnitude. It is the ratio of vector itself by its magnitude.

Thus,the magnitude of a unit vector is one.

**Scalar or Dot Product of Two Vectors**: