Clairaut first integral for a surface of revolution
= Clairaut first integral for a surface of revolution
{c}
= Clairaut's relation
{c}
{synonym}
For a geodesic in the metric $du^2+Y(u)^2dv^2$, the cyclic coordinate $v$ gives
$$
Y(u)^2\dot v=\text{constant}.
$$
Equivalently, the geodesic meets parallels according to Clairaut's relation.