His main work was probably done about the beginning of the eleventh century, and seems to have taken an important part in the elaboration of trigonometry. He wrote also an astrological introduction and an arithmetic treatise Kitab fi usul hisab al-hind Principles of Hindu Reckoning , extant in Arabic and Hebrew. He was the teacher of Ahmad Nasawi. He is thought to have died in Baghdad. From Wikipedia, the free encyclopedia.

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Biography Kushyar ibn Labban was from the village of Gilan, which was situated south of the Caspian sea in Persia. He is known by several different variants of his name, which has been transliterated as Kusyan, Kushiyad, Koshar, Kusiar or Kossar. Sometimes he has been called Jabah, Halebi and al-Kiya. The name Labban, sometimes written as Labbar, was his father's name and means "lion". Very little is known of Kushyar ibn Labban's life.

There are various different claims, one of which suggests that he was a Jew, but none are substantiated. The only fact which is certain, other than the material in his works, is that he taught al-Nasawi. From his works we know that Kushyar was primarily an astronomer who wrote texts on astronomy and geography.

He produced astronomical tables and also wrote a work on the astrolabe. Most significant in terms of this archive is his work on Hindu reckoning being the earliest known work on Arabic arithmetic which deals with Hindu numerals.

An earlier text by Abu'l-Wafa on arithmetic did not use Hindu numerals. Kushyar's Principles of Hindu reckoning was written about AD. In [ 1 ] its importance is described as follows:- Kushyar ibn Labban's Principles of Hindu reckoning It may be the oldest Arabic mathematical text using Hindu numerals, and ibn Labban's concepts reveal considerable originality Let us consider the Principles of Hindu reckoning in a little more detail.

The first point to note is that Kushyar uses a symbol for zero, but does not use any separating symbol to distinguish the fractional part of a number from the integral part. He discusses decimal numbers in the main body of the text, relegating sexagesimal numbers to a separate treatment in tables. Topics considered include addition and subtraction of decimal numbers followed by multiplication and division of decimal numbers.

Kushyar gives methods to construct exact square roots, as well as approximate methods to calculate the square roots of non-square numbers. Similarly he gives methods to construct exact cube roots, and an approximate method to calculate the cube root of a non-square number.

As a check on the accuracy of his results, Kushyar uses the method of "casting out nines" or "checking the nines" which basically checks that the sums are correct modulo 9. Levy and Petruck write in [ 1 ] :- Ibn Labban's Arabic text was written in a highly abbreviated style that must have been difficult to understand when studied alone. It is easily seen, therefore, why al-Nasawi found it worthwhile to elaborate on the work of his teacher Other Mathematicians born in Iran.

References show. M Levey and M Petruck trs. Additional Resources show.


Kushyar ibn Labban

Kushyar ibn Labban was an Iranian astronomer and mathematician who was active around A. It is written in Arabic, the scientific language in the Islamic territories in Kushyar's time, and consists My Ph. Approximately Zijes by different authors in the Islamic astronomical tradition from the ninth to fifteenth centuries A. A Zij usually contains tables with instructions for use for the computation of solar, lunar and planetary positions. These computations are often based on the methods of Ptolemy's Almagest ca. Zijes are often also provided with auxiliary trigonometrical tables, tables for lunar crescent visibility and prayer times, tables of geographical and stellar coordinates, astrological tables, materials on calendars and tables for calendar conversions.


Kushyar Gilani

Enter your mobile number or email address below and we'll send you a link to download the free Kindle App. Then you can start reading Kindle books on your smartphone, tablet, or computer - no Kindle device required. To get the free app, enter your mobile phone number. Would you like to tell us about a lower price? If you are a seller for this product, would you like to suggest updates through seller support? The Principles of Hindu Reckoning is an important arithmetical treatise which displays the sexagesimal system and the concept of "marks". Read more Read less.

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