Clairaut's relation, named after Alexis Claude de Clairaut, is a formula in classical differential geometry. The formula relates the distance r(t) from a point on a great circle of the unit sphere to the z-axis, and the angle θ(t) between the tangent vector and the latitudinal circle:
The relation remains valid for a geodesic on an arbitrary surface of revolution.
- M. do Carmo, Differential Geometry of Curves and Surfaces, page 257.
See also 
|This Differential geometry related article is a stub. You can help Wikipedia by expanding it.|