Qin Jiushao (redirected from Qin Jiu-shao)

Qin Jiushao

(born c. 1202, Puzhou, China—died c. 1261, Meizhou) Chinese mathematician who developed a method of solving simultaneous linear congruences. In 1219 he joined the army as captain of a territorial volunteer unit and helped quash a local rebellion. In 1233 he began his official government service. In his only mathematical book, now known as Shushu jiuzhang (1247; “Mathematical Writings in Nine Sections”), he introduced a method of solving systems of linear equations that was rediscovered in Europe about 1802, where it became known as the Ruffini-Horner method. He later became provincial governor of Qiongzhou, but charges of corruption and bribery brought his dismissal in 1258.