Habash al-Hasib al-Marwazi

Full name: 
Ahmad ibn 'Abdallah Habash Hasib Marwazi
Date of death: 
869
Ahmad ibn 'Abdallah Habash Hasib Marwazi was a Persian astronomer, geographer, and mathematician from Merv in Khorasan who described first time Trigonometric ratios: SIN ,COS, TAN & COT.
 
He flourished in Baghdad, and died a centenarian after 869. He worked under the Abbasid caliphs al-Ma'mun and al-Mu'tasim.