Ibn Mu'adh al-Jayyani facts for kids

Abū ʿAbd Allāh Muḥammad ibn Muʿādh al-Jayyānī (989–1079) was a brilliant Arab mathematician and astronomer. He lived in Al-Andalus, which is now part of Spain. Al-Jayyānī was also a Qadi, meaning a judge in Islamic law.

He is well-known for writing important notes on Euclid's Elements. This is a very old and famous book about geometry. Al-Jayyānī also wrote the first known book specifically about spherical trigonometry. This is a special kind of math that helps us understand shapes on the surface of a sphere.

Life

We don't know many details about Al-Jayyānī's personal life. He was born in Cordova in 989. He passed away in Jaén in 1079. Both of these cities are in Al-Andalus, which was a Muslim-ruled area in what is now Spain.

Al-Jayyānī's Book on Spheres

Al-Jayyānī wrote a very important book called The book of unknown arcs of a sphere. Many people consider this the first book focused entirely on spherical trigonometry.

Spherical trigonometry is a branch of geometry that deals with triangles on the surface of a sphere. Imagine drawing a triangle on a globe; that's what spherical trigonometry studies.

Before Al-Jayyānī, mathematicians like Menelaus of Alexandria worked on spherical problems. They used something called Menelaus' theorem. However, applying this theorem to solve problems on a sphere was very difficult.

Al-Jayyānī's book made it much easier. It included new ways to solve problems with spherical triangles. His work showed how to find unknown parts of these triangles. It also contained the general law of sines for spheres. This law helps you find missing sides or angles in a triangle.

His book had a big impact on European mathematics later on. His ideas about how to define ratios as numbers were important. Also, his method for solving a spherical triangle when all its sides are unknown likely influenced later mathematicians like Regiomontanus.

See also

In Spanish: Ibn Mu'adh al-Jayyani para niños

• List of Arab scientists and scholars
• Islamic mathematics