Daily conversations   Food & Restaurant   Travel & Car   Family   Home   Occupations   Kitchen   Week days & Seasons   School   Numbers   Colours   Parts of human body   Things   Persian language   Persian alphabet   Persian grammar   Persian Music   Persian foods   Persian poems   Iranian scientists   English words of Persian origin   Free Downloads   Support   Feedback   Upload your video   Search	Category  »  Iranian scientists                                  Abu Wafa Buzjani, mathematician. Abul Wafa Muhammad Ibn Muhammad Ibn Yahya Ibn Ismail Buzjani (940 – 997 or 998) was a Persian mathematician and astronomer. He was born in Buzhgan, Nishapur in Iran. 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. 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 sine formula for spherical geometry (which looks similar to the law of sines): 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 and there is a crater called Abul Wáfa (crater) on the moon. Source: wikipedia.org Previous Related links: Al-Qumri, a Persian physician. Bukhtishu, Abdollah ibn, physician Esfarayeni, physician Ghazzali (Algazel), philosopher Hajji Zayn al-Attar, physician Add this page to Your Favorites   Previous
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