(1) | |||

(2) |

where the unit Tangent Vector and unit ``principal'' Normal Vector are defined by

(3) | |||

(4) |

Here, is the Radius Vector, is the Arc Length, is the Torsion, and is the Curvature. The binormal vector satisfies the remarkable identity

(5) |

**References**

Kreyszig, E. ``Binormal. Moving Trihedron of a Curve.'' §13 in
*Differential Geometry.* New York: Dover, p. 36-37, 1991.

© 1996-9

1999-05-26