Ellipsoidal coordinates

This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. Please help improve this article by introducing more precise citations. (April 2021) (Learn how and when to remove this message)

Ellipsoidal coordinates are a three-dimensional orthogonal coordinate system ${\displaystyle (\lambda ,\mu ,\nu )}$ that generalizes the two-dimensional elliptic coordinate system. Unlike most three-dimensional orthogonal coordinate systems that feature quadratic coordinate surfaces, the ellipsoidal coordinate system is based on confocal quadrics.