Who Was Fibonacci and What Was He Famous For?

Fibonacci, or Leonardo Pisano, was born in 1170 in Pisa, which is now part of Italy. Though an Italian Native, Fibonacci went to school in Bugia (Pastor), a town in Northern Africa where his father, Guiliano Bonacci (Bruno), was stationed and working as a foreign diplomat (O'Connor). The nickname "Fibonacci", by which Pisano is most commonly known, is said to have come from a shortened version of the Italian "Son of Bonacci" , or "filo Bonacci." It is unknown wether the name was given to Fibonacci after his before or after his death or wether he coined it himself of recieved and accepted the name. He was, however, known to refer to himself by the name "Biggolo," after a derogatory term refering to one who was with many women (Bruno).

Around 1200, Fibonacci returned to Pisa from Bugia. Soon after, he went to work as a mathematician and scientist for the Roman emperor FrederickII (Bruno), a remarkable young man described by Fibonacci as having "piercing blue eyes which are said to made his courtiers tremble." The emperor encouraged learning of all kinds and often sent scholars to present FIbonacci with difficult math problems for him to solve (Horadam).

Not long after this appointment (in 1202 AD), Fibonacci published his first of many and by far his most famous book, the Liber Abaci. This infamous book is responsible for the introduction of the Arabic numeral system (the numeral system we use today for mathematics and in everyday written communication) to Europe. It also explains in great detail what were then new and more accurate methods of solving quadratic equations, information about Fibonacci's infamous sequence of numbers and his :golden ratio" (Devlin).

Three more books of mathematics are known to have been published by Fibonacci; Practica Geometriae, Liber Quadratarum, and Flos. In the four long volumes published by him, Fibonacci explains, in detail, methods for solving the cube root of a number, specific algebraic equations and their solutions, the Arabic numeral system, the introduction of the division bar into mathematic longhand calculations, the golden ratio or golden number, the Fibonacci sequence (from which the golden ratio is derived), and much, much more (Devlin).

Fibonacci is perhaps most commonly known for his famous "Fibonacci Sequence." This sequence is derived by adding the previous two numbers of the sequence to form next number, for example: 1, 1, 2, 3, 5, 8, 13, 21, 34...etc. (1+1=2, 1+2=3, 2+3=5, 3+5=8... etc.). This sequence appears in many living things, such as snail shells, the leaves of a plant, conchs, pinecones, pineapples, palm tree trunks, sunflowers, and flower petals. It also appears quite frequently in music. There are many recurring patterns in music that show up frequently because they sound pleasing to the ear ("Fibonacci").

Fibonacci's golden ratio is also extremely well known in educated circles. The ratio is found by finding the limit of each number divided by the previous number as the sequence reaches infinity ( 1, 2/1 = 2, 3/2 = 1.5, 5/3 = 1.666..., 8/5 = 1.6, 13/8 = 1.625, 21/13 = 1.61538... ). The limit works out to be approximately 1.61804 ("Fibonacci").

No one knows for certain where, when, or how Fibonacci died, but he is thought to have passed away in Pisa in the year 1250 (Pastor). Though we know very little about the man that was Fibonacci, the influence he had on our lives is indisputable. Even those who are not mathematically inclined or good with numbers can appreciate the value of looking at a speed limit sign and seeing "35 mph" instead of "XXXV mph".

Works Cited

Bruno, Leonard C. Math & Mathematicians: The History of Math Discoveries Around the World. Vol. 1. Farmington Hills MI: The Gale Group, 1999.

Devlin, Keith. "The 800th Birthday of the Book that Brought Numbers to the West." Stanford University. 19 May 2009 .

Horadam, A. F. "FIBONACCI." University of Evansville Faculty Web sites. 1975. University of New England. 19 May 2009 .

"Fibonacci." Email Portal. 19 May 2009 .

O'Connor, J. J. "Fibonacci biography." MacTutor History of Mathematics. 1998. 19 May 2009 .

Pastor, Francisco M. "Biografia de Leonardo Pisano Fibonacci." Astroseti : Astronom. 21 May 2009 .