Al-Khwarizmi

Abu Ja'far Muhammad ibn Musa Al-Khwarizmi was born around 780 A. D. in the Khwarizm region of Eurasia, by the Aral Sea, under the reign of Caliph al-Rashid. All that we know about al-Khwarizmi’s life, which really is not that much, comes from the works of ancient historians, some of whom were not that reliable, and from prefaces to al-Kwharizmi’s own writing. It is from one such preface that we know he was a devout Muslim, dedicated to his Caliph and his work. Some challenge this general (and probably correct) notion that he was a Muslim born in Khwarizm, as al-Taberi, a historian, also added “ al-Majusi al-Qutrubbulli” to al-Kwharizmi’s name. This would place him as a follower of the Zoroastrian faith from the Qutrubbull region by Baghdad. However, it is more likely that this referred to his ancestors or another person, given the information from the preface al-Khwarizmi wrote clearly identifies him as an adherent of Islam. Under the Caliphate of al-Mamun the House of Wisdom, a place of study, was set up in Baghdad. Al-Khwarizmi worked there translating Greek scientific and mathematical writings, as well as composing his own scientific works. He probably kept up to date on all advances in the world of science and math in that part of earth. After a long fulfilling life full of mathematics, astrology, geography, and the like he died in circa 840 A.D.

His most well known contribution to the world is his book //Algebra.// In Arabic its title is //Hisab al-jabr w'al-muqabala//, which means “The Compendious Book on Calculation by Completion and Balancing” (Encyclopedia Britannica Online, 2008). It is from the word al-jabr, (to which this work often was called), we get, when translated into Latin, the word algebra (This book is also the one with the aforementioned prefix). //Algebra// has three parts. Only the first part is actually algebra. It deals with equations and variables, and he held that all equations could be simplified to one of six forms. He did not take into account zero or negative numbers as coefficients, however. Not only did he not use certain numbers, but he also did not use numerals. He wrote the entire //Algebra// with words! Imagine trying to write out how to do a specific equation, with only words, and without even the concept of numerals. //Algebra// is full of such problems. However, he did use geometric proofs, like the Greeks, as you can see in the picture to the left. The second part of //Algebra// is about the measurement of areas and volumes of geometric figures, like circles, pyramids, and cones, and finding prices and quantities. The third and final part deals with the rather complicated Muslim laws of inheritance. Some say that the most important thing about this book of rather elementary algebra is that it synthesized Greek, Hindu, and Hebrew sources, as did many of al-Khwarizmi's other works, which was a great accomplishment for the advancement of math. Another of those important works is a treatise on the Hindu numerals 0-9. Like many pieces of his, all that we know of it are translations and references. It is this paper that greatly popularized the numbers we use today, though they were mislabeled Arabic by the Romans. Without this work it would have taken longer for the quick-to-write Hindu numerals to reach the west. Al-Khwarizmi also wrote an influential astronomical work, with positions of the sun and planets, calendars and astrology. He also did some map work in his //Geography//, which was more accurate in places then Ptolemy’s, and some minor papers on astrolabes, sundials, and the Jewish calendar. Aside from all these books and writings, he worked on sine tables and operations on fractions. He even worked on a project for al-Mamun to find the circumference of the earth.

The Romans also made one more taxonomical error that greatly affected the western world. Because of this, you have all heard of Al-Khwarizmi before you even knew who he was. In Latin his name became Algorism, and from there it went to algorithm. So next time you use an algebraic algorithm, think of the ancient Islamic scholar al-Khwarizmi, whose work on algebra and numerals revolutionized the western perception of mathematics.

Citations:

"**Khwarizmi, al-**." __Encyclopædia Britannica__. 2008. Encyclopædia Britannica Online. 6 Mar. 2008 <[|http://www.britannica.com/eb/article-9045366>.] Toomer, G J. __Dictionary of Scientific Biography__. New York : 1970-1990.

Ahmed, Monzur. __MOHAMMAD BIN MUSA AL-KHAWARIZMI__. 18 July 1998. March 5 2008 <[|http://www.ummah.net/history/scholars/KHAWARIZ.html>.] O'Connor, J J and E F Robertson. __Al-Khwarizmi biography__. July 1999 School of Mathematics and Statistics University of St Andrews, Scotland. March 5 2008 .

Asimov, Isaac. __Asimov's Biographical Encyclopedia of Science and Technology__. Doubleday, 1972.