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Buzjani, the Persian mathematician and astronomer.

Abul Wafa Buzjani (10 June 940 – 1 July 998)^[1] (Persian: ابوالوفا بوزجانی), extended name: Abū al-Wafāʾ Muḥammad ibn Muḥammad ibn Yaḥyā ibn Ismāʿīl ibn al-ʿAbbās al-Būzjānī (Persian: ابوالوفا محمد بن محمد بن یحیی بن اسماعیل بن العباس البوزجانی) was a Persian mathematician and astronomer. He was born in Buzhgan, (now Torbat-e Jam) in Iran.

In 959 AD, he moved to Iraq. He studied mathematics and worked principally in the field of trigonometry. He wrote a number of books, most of which no longer exist. He also studied the movements of the moon. The crater Abul Wáfa on the Moon is named after him.

Astronomy

He devised a wall quadrant for the accurate astronomy measurement of the declination of stars. He also introduced the tangent function and improved methods of calculating trigonometry tables and developed novel ways of solving some problems of spherical triangles.

Mathematics

He established the trigonometric identities:

sin(a + b) = sin(a)cos(b) + cos(a)sin(b)

cos(2a) = 1 − 2sin²(a)

sin(2a) = 2sin(a)cos(a)

and discovered the law of sines for spherical triangles:^[2]

See also

• List of Iranian scientists

Further reading

• Youschkevitch, A.P. (1970). "Abul Wafa al-Buzjani, Muhammad Ibn Muhammad Ibn Yahya Ibn Ismail Ibn Al-Abbas". Dictionary of Scientific Biography. 1. New York: Charles Scribner's Sons. pp. 39–43. ISBN 0684101149.  
• O'Connor, John J.; Robertson, Edmund F., "Mohammad Abu'l-Wafa Al-Buzjani", MacTutor History of Mathematics archive, http://www-history.mcs.st-andrews.ac.uk/Biographies/Abu'l-Wafa.html  .

References

1. ^ "بوزجانی". Encyclopaediaislamica.com. http://www.encyclopaediaislamica.com/madkhal2.php?sid=2053. Retrieved 2009-08-30.  
2. ^ Jacques Sesiano, "Islamic mathematics", p. 157, in Selin, Helaine; D'Ambrosio, Ubiratan (2000), Mathematics Across Cultures: The History of Non-western Mathematics, Springer, ISBN 1402002602