We need the time derivatives of the unit vectors.
This article will deal only with unit vectors in 2-dimensional space (R) but the method described can be extended to the general case.
A unit vector is often indicated with a hat as in â.
The unit vectors define a coordinate system fixed on the primary body.
The opposite is true for the dot product of two unit vectors.
As mentioned above, a state of a quantum system is given by a unit vector in a Hilbert space.
The above mentioned triad of unit vectors is also called a basis.
Similarly unit vectors can be used to simplify the calculations.
These unit vectors need not be related to the tangent and normal to the path.
The letter is sometimes used to denote a unit vector in mathematics.