Chronological Order -399 pythagoreans discover irrational numbers -240 Eratosthenes determines circumference of earth -230 Archimedes determines fromulas for the area of a secton of a parabola formulas for the area of a section of a parabola -200 Appollonius studies conic sections -200 Euclid writes Elements -100 Hipparchus develops the trig tables 825 Al-Khowarizmi uses Zero 1525 Rudolff introduces the radical sign 1535 Tartaglia solves cubic equations 1545 Square roots of negative numbers 1557 Recorde introduces the equals sign 1565 Goldbach states famous conjecture 1614 Napier invents logarithms 1614 Briggs uses base 10 logarithms 1621 Harriot introduces the inequality signs 1630 Oughtred invents the slide rule 1637 Descartes creates analytic geometry 1641 Descartes’ Geometrie was published 1654 Pascal and Fermat discuss theory of probability in their correspondence 1655 Wallis introduces the symbol for infinity 1660 Fermat leaves last theorem 1665 Newton invents calculus 1669 Barrow discovered the general solution for the tangent line to a curve 1675 Leibniz invents calculus 1696 L’Hopital wrote the first text on differential calculus 1715 Brook Taylor’s published account of polynomial approximations of transcental functions 1742 Goldbach states famous conjecture 1748 Agnesi writes Foundations of Analysis 1755 Euler shows that ePi i + 1 = 0 that epi i + 1 = 0 1770 Lambert proves pi is irrational 1773 Saccheri writes Euclid Freed of Every Flaw 1797 Lagrange proved the Mean Value Theorem 1814 Argand graphs imaginary numbers 1828 Gauss determines the convergence of infinite series 1830 Galois writes agout group theory 1842 Lovelace describes how to program Babbages Analytical Engine 1854 Riemann creates elliptic geometry 1854 Cayley uses matrices in solving equations 1858 Mobius strip is discovered 1888 Kovalevski is the first woman to earn a doctorate in mathematics 1895 Cantor creates transfinite numbers 1905 Einstein publicly formulated his theory on relativity 1910 Whithead and Russell write Principia Mathematica 1919 Alice Hamilton is Harvard’s first female professor 1931 Godel publishes incompleteness theorems 1942 ENIAC, the first electronic computer is invented 1974 Mrs. Greminger became a mathematics instructor at Valle High School 1975 Bill Gates started his computer company Microsoft 1976 Four color map problem is solved 1998 Mrs. Moll became a mathematics instructor at Valle High School.