Wada Yasushi

Wada Yasushi ( Japanese 和田 寧 ; * 1787 in Edo , Harima Province ; † 1840 ), or Wada Nei (the Sino-Japanese reading of his name), was a Japanese mathematician of Wasan .

He was born in Edo in 1787 and was originally called Kōyama Naoaki. He first worked in the Buddhist Zōjōji ( 増 上 寺 ) in Edo. Eventually he left the temple and, for reasons unknown, changed his name to Wada Nei. Under the auspices of Prince Tsuchimikado at the court of Mikado, he began to study mathematics. He studied with Kusaka Makoto ( 日下 誠 ), who in turn was a student of Ajima Naonobu .

Wada Nei improved the integral calculus developed by Ajima Naonobu for the Enri ( 円 理 , dt. "Circle principle") corresponding to the exhaustion method . He dealt with the determination of extreme points by the Enri and provided a detailed explanation of a method going back to Seki Takakazu (equivalent to examining the zeros of the derivative). He was also the first Japanese mathematician to study roulette curves.

See also

• History of mathematics

literature

• David Eugene Smith , Yoshio Mikami : A History of Japanese Mathematics . Open Court Publishing, Chicago 1914 ( full online version at archive.org )

Japanese name: As is common in Japan, the family name comes before the first name in this article . Thus Wada is the family name, Yasushi the first name.