important math developments

Leonardo Fibonnacci develops the Fibonnacci sequence

Jun 18, 1202

Ferrari solves a quartic equation

Jun 18, 1540

Descartes uses the term imaginary number

Jun 18, 1647

Isaac Newton develops the fundamental theorem of calculus

Jun 18, 1665

http://en.wikipedia.org/wiki/Fundamental_theorem_of_calculus

Leibniz discovers technique of separation of variables

Jun 18, 1691

http://en.wikipedia.org/wiki/Gottfried_Wilhelm_Leibniz