# Mathematician:Abu'l-Wafa Al-Buzjani

## Mathematician

Persian mathematician and astronomer who made important innovations in spherical trigonometry.

His work on arithmetic for businessmen contains the first instance of using negative numbers in a medieval Islamic text.

Credited with compiling the tables of sines and tangents at $15'$ intervals

Introduced the secant and cosecant functions, and studied the interrelations between the six trigonometric lines associated with an arc.

His Almagest was widely read by medieval Arabic astronomers in the centuries after his death. He is known to have written several other books that have not survived.

Known for his study of geometrical dissections.

Pioneered the technique of geometrical construction using a rusty compass.

## Nationality

Persian

## History

- Born: 10 June 940 in Buzjan (near Jam), Khorasan region (now in Iran)
- Died: 15 July 998 in Baghdad (now in Iraq)

## Theorems and Definitions

## Publications

*كتاب المجسطي (Kitāb al-Majisṭī)*("Almagest")

*زيج الواضح (Zīj al‐wāḍiḥ)*(no longer extant)

*كتاب في ما یحتاج إليه الصانع من الأعمال الهندسية (Kitāb fī mā yaḥtāj ilayh al-ṣāniʿ min al-aʿmāl al-handasiyya)*("*On Those Parts of Geometry Needed by Craftsmen*")

*كتاب في ما يحتاج إليه الكتاب والعمال من علم الحساب (Kitāb fī mā yaḥtāj ilayh al-kuttāb wa’l-ʿummāl min ʾilm al-ḥisāb)*("A Book on What Is Necessary from the Science of Arithmetic for Scribes and Businessmen")

## Also known as

Full name: **Muḥammad ibn Muḥammad ibn Yaḥyā ibn Ismāʿīl ibn al-ʿAbbās al-Būzjānī**.

Usually known as **Abū al-Wafāʾ** or **Abu'l Wefa** or some such.

Transliteration varies.

## Sources

- John J. O'Connor and Edmund F. Robertson: "Abu'l-Wafa Al-Buzjani": MacTutor History of Mathematics archive

- 1991: David Wells:
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