Deep relations between elliptic functions and Cartesian ovals were also established in 1867, with the geometrical proofs of the addition theorem of elliptic functions given by Darboux and Laguerre.
Malalim na ugnayan sa pagitan ng mga function at tambilugin Kartesyan ovals din ay naitatag sa 1867, kasama ang heometriko proofs ng karagdagan teorama ng tambilugin function na ibinigay ng Darboux at Laguerre.