Princess Sofia (Sophie in Sweden) of Nassau, (July 9, 1836 - December 30, 1913), was the daughter of George William Augustus Henry, Duke of Nassau-Weilburg and his wife Pauline Friederica Marie Princess of Württemberg.
... the formula should be understood as "either of those element(s) of the field whose square equals b2 - 4ac". In some fields, some elements have no square ...