principle of mechanics, which he believed to be part of the
mathematical sciences. He is most known for his work on the
equilibrium and motion of fluids entitled Traité de l’equilibre
et du mouvement des fluides,his article on vibrating strings in
which he was the first to publish the wave equation (even
though it was flawed), his pioneering work on partial
differential EQUATIONs in physics, and his extensive scientific
writings on philosophy and mathematics, most notably
PROBABILITYand geometry, for the 28-volume Encyclopédie,
as well as d’Alembert’s RATIOtest.Apollonius of Perga (ca. 262–190 B.C.E.) The Greek mathematician
often called “the Great Geometer,” whose most famous work is
his text on conics, also worked with TANGENTs, RATIOs, and
inclinations, among others. He coined such terms as
PARABOLA,HYPERBOLA, and ellipse, and gave an
approximation for pi as 3.1416, although he never explained
how he arrived at this VALUE.Argand, Jean-Robert(1768–1822) A self-taught amateur
mathematician, this Swiss native lived in Paris and worked on
creating his most renowned work, graphing COMPLEX
NUMBERs of the form a+bi,using one AXISto represent
IMAGINARY NUMBERs, and the other to represent REAL
NUMBERs, which is now known as the Argand diagram. His
book on this subject, Essai sur une manière de représenter les
quantitiés imaginaires dans les constructions géométriques,
was originally self published, and his authorship was unknown
for seven years. He shares credit for originating this idea with
Caspar Wessel, whose paper on the same topic was published
in 1799 but went unnoticed by the mathematical community.
Argand’s impressive body of work also included a PROOFon
the FUNDAMENTAL THEOREM OF ALGEBRA, in which he was the
first person to use complex numbers for the COEFFICIENTs.Archimedes of Syracuse(ca. 287–12 B.C.E.) Ancient Greek
considered with SIR ISAAC NEWTONand KARL FRIEDRICH
GAUSSto be one of the three greatest mathematicians of all
time, he is best known for his geometry and his mathematical-
intensive inventions, such as the catapults used to protect
Syracuse during a three-year siege, and the Archimedean
screw, a corkscrew-like device used to move water out ofBIOGRAPHIES Apollonius of Perga – Archimedes of Syracuse
BIOGRAPHIES Apollonius of Perga – Archimedes of Syracuse