Fibonacci

Biography--- Leonardo Fibonacci was born in Pisa, Italy around 1175. The time during which Leonardo would present his findings was still considered part of the medieval period, a time when Europe seemingly held little interest in scholarship. However, interest in his work became widespread, contributing to Fibonacci’s importance along with the publication of several of his works. Science and art were being reintroduced into the west, and Europe was emerging from its isolation, resuming trade with northern Africa and the Middle East. Fibonacci’s father, Guilielmo, was a secretary of the Republic of Pisa, and in 1192 he was sent to the trading colony of Bugia, (now Bougie) Algeria to represent merchants in the fur and leather trade. He took Leonardo with him so he could be educated in the art of calculating, since he expected his son to become a merchant one day. There, in Bugia, Fibonacci learned methods “with the new Indian numerals” better known as Hindu or Arabic numerals, which we use commonly today, (1,2,3,4,5,6,7,8,9) These were quite different from the Roman numerals his people used at the time, and he found them far more convenient. (Compare writing 1998 in Roman numerals to Arabic numerals...MDCCCCLXXXXVIII versus 1998, and now imagine doing simple mathematical equations using Roman numerals, compared to Arabic) Also, the Arabic numerals included zero. Fibonacci's father sent him on business trips to Egypt, Greece, Syria, Sicily, Provence, and other various countries, where he continued to learn and compare the different methods each country used in mathematics, and often found them conflictive when compared to the Indian methods. It was approximately the year 1200 when Fibonacci refrained from traveling and returned to Pisa to record his findings, which resulted in //Liber abbaci//, a book of calculations (1202) //Practica geometriae// (1220) //Flos// (1225) and //Liber quadratorum//. After the publication of his first book, Leonardo drew the attention of scholars in the court of Frederick II, a Holy Roman Emperor, and he remained in their correspondence, (including astronomer Dominicus Hispanus). Later Leonardo may have been awarded a yearly state pension, or salary, in 1228. A document from 1240 states he was still receiving state sponsorship from Pisa at that time. This is the last record of him we have today. Leonardo Fibonacci likely died between 1240 and 1250.

Mathematical Contributions---

Fibonnaci was a brilliant problem solver in the fields of Algebra and number theory. He is perhaps most associated his namesake series of "Fibonacci numbers", a sequence where in its simplest form each number is the sum of its two predecessors, (1,1,2,3,5,8,13,...) This sequence has been applied in various ways in surprisingly diverse fields, from botany and music to psychology. One of its applications can even be found in astronomy, where a more exact correspondence is used in Bode's law to the distances between planets and the sun. With the publication of //Liber abbaci//, Fibonacci introduced a problem using this sequence involving the population growth of rabbits. Edouard Lucas (1842-1891) popularized this number sequence when he produced many new and important applications for it, referring to the sequence throughout his works as "Fibonacci numbers". While the name stuck, the sequence had already been discussed before Leonardo wrote his book by Indian scholars who'd long held an interest in rhythmic patterns formed from one-beat and two-beat notes. Fibonacci also introduced the Arabic-Hindu place-valued decimal system to Europe, as well as the Arabic numbers which we commonly use today, ( 0,1,2,3, etc..) In //Practica geometriae//, he produced problems applicable to land surveying, borrowing portions of Euclid's "Elements". //Liber quadratorum,// or the book of squares, was on finding Pythagorean triples. He is also credited with proposing the idea of a bar, (solidus) which resulted in the fractions we use today. Fibonacci helped bring mathematics back to western civilization. Through his introduction of concepts and his work in applications and formulas for the people's use, he helped brought mathematics back into the light.

Sources---

Gillispie, Charles Coulston, ed. __Dictionary of Scientific Biography__. New York: Charles Scribner's Sons, 1980.

Knott, Dr. Ron. __Who Was Fibonacci?__. 11/21/07 University of Surrey. 2/24/08 <[|http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/fibBio.html>.]

"Leonardo Fibonacci (c. 1170-c. 1250)." Hutchinson's Biography Database. EBSCOhost, 2/24/08 <[|http://search.ebscohost.com/login.aspx?direct=true&db=mih&AN=7I7M0001287&site=ehost-live]>.

O'Connor, J J, and Robertson E F. __Leonardo Pisano Fibonacci__. 1998. 

Pearson, John. __Leonardo of Pisa (Fibonacci)__. New York: Great Neck Publishing, 2006.