A unit vector is any vector that is one unit in length.
Unit vectors are often notated the same way as normal vectors, but with a mark over the letter (e.g. is the unit vector of a.)
To make a vector into a unit vector, divide it by its length:
In component form[change | change source]
Three common unit vectors used in component form are , and , referring to the unit vectors for the x-, y- and z-axes respectively. They are commonly just notated as i, j and k.
They can be written as the following: