Ajima Naonobu

Naonobu is a redirect to this article. For the moon crater, see Naonobu (moon crater) .

Ajima Naonobu ( Japanese 安 島 直 円 ; * 1732 in Shiba, Edo (today Minato , Tokyo ), † November 14, 1798 in Edo), also Ajima Chokuen (the Sino-Japanese reading of his name) or Ajima Chokuyen (outdated for Chokuen ), was a Japanese mathematician of Wasan .

He developed, among other things, the integral calculus of Enri ( 円 理 , dt. "Circle principle"), which corresponds to the exhaustion method , the approximation of the circle by polygons similar to Archimedes . He also extended this integration method to three dimensions (solving the problem of finding the volume of the intersection of two cylinders). He also created tablets of logarithms, which became known in Japan through Jesuit missionaries in China (a related book Suri Seiran appeared in China in 1723). He was also known for a geometrical-algebraic problem, the Gion-Shrine problem. It led to an equation of the tenth degree, which he solved numerically. He also formulated Malfatti's problem thirty years before Gianfrancesco Malfatti (see Malfatti circle ).

His father was the chairman of the treasury ( 御 勘定 頭 , o-kanjō-gashira ) of the Shinjō fief . He became a relatively late student of the mathematician and astronomer Yamaji Nushizumi in Edo (Tokyo) from the school of Seki Takakazu .

The lunar crater Naonobu is named after him.

literature

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

Web links

• John J. O'Connor, Edmund F. Robertson :  Ajima Naonobu. In: MacTutor History of Mathematics archive .

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