Sur le Point de Rebroussement de la seconde Espece de mr. le Marquis de l'Hopital. (On the nispidal points of the second kind of Mons. le Marquis de l'Hopital). (+) Recherches sur les Racines Imaginaires des Equations. (Research on imaginary roots o...

(Berlin, Haude et Spener, 1770). 4to. No wrappers, as issued in ""Mémoires de l'Academie Royale des Sciences et Belles-Lettres"", Tome V, pp. 203-221, 1 plate and pp. 222-288, 1 engraved plate.

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Both papers first edition. The first paper is Euler's discussion of ""Cramers Paradox"" and it contains his inventions of 2 kinds of curves, ""Cusps of first kind"" or keratoid cusp and ""Cups of second kind"" or ramphoid cusp. - Enestroem E 169.The second paper contains Euler's famous proof of ""The fundamental Theorem of Algebra"". - Enestroem E 170.