Makers › Mathematician
Zu Geng
Son of Zu Chongzhi who got his father's calendar adopted by the Liang and derived the volume of a sphere from the principle that equal cross-sections give equal volumes
In a calculation room, a wide table holds a board of black and yellow counting rods laid in neat bundles, beside an abacus, a ruler and a sheet with a circle divided into equal parts; one person sits at a far desk with their back turned, and terraced fields lie outside.
Also known as Zu Gengzhi
Zu Geng, also called Zu Gengzhi, courtesy name Jingshuo, was a son of the mathematician Zu Chongzhi and came from Qiu county in Fanyang. The History of the Southern Dynasties (Nanshi) says he inherited the family learning and was so absorbed in thought that thunder could not reach him; once, walking lost in calculation, he bumped into the chief minister Xu Mian and only came to when Xu called out. His father's calendar had never been adopted under the Song or Qi, so early in the Liang Tianjian reign he revised and resubmitted it, and it came into use in 510. Li Chunfeng's Tang commentary on the Nine Chapters on the Mathematical Art (Jiuzhang suanshu) preserves his method for the sphere, resting on the rule that solids with equal cross-sections at every height have equal volumes. He rose to director of waterways, and in 525, serving under Xiao Zong at Pengcheng, he was held by the Northern Wei when Xiao defected, and was later released.
Life and times
Dates Dates unknown; active in the early 6th century