Abu al-Wafa al-Buzjani

Known for

Advanced trigonometry: the tangent function and the spherical law of sines

Biography

Persian mathematician from Buzhgan (Khorasan) who worked at the Buyid observatory in Baghdad.

Contributions

• Introduced the tangent function and built tables of sines and tangents
• Proved the law of sines for spherical triangles
• Wrote a practical arithmetic book for scribes and merchants

Major works

• Kitab al-Majisti (Almagest)
• Kitab fi ma Yahtaj ilayh al-Kuttab wa al-Ummal min 'Ilm al-Hisab (arithmetic for scribes)