Toshikiyo Kamata

Japanese: 鎌田俊清 - かまた・としきよ

Year of death: 1747
Year of birth: Enpo 6 (1678)
A Japanese mathematician in the mid-Edo period. Born in Osaka. His detailed career is unknown. He was the third brilliant master of the Takuma school, which developed in Osaka independently of the Seki school (the first master was Takuma Yoshikiyo, also from Osaka). He wrote Takuma-ryu Enri in 1722, the same year as Takebe Katahiro's Tsuijutsu Sankei. In this work, Kamata makes full use of infinite series to formulate the expansion of sinx and arcsinx, and calculates the perimeter of a regular 244-polygon inscribed and circumscribed in a circle to find pi to about 25 decimal places. The fact that similar discoveries were made in both eastern and western Japan by chance is an interesting example of "simultaneous scientific discoveries." <References> The History of Mathematics in Japan Before the Meiji Era, edited by the Japan Academy, Vol. 3

(Kenichi Sato)

Source: Asahi Japanese Historical Biography: Asahi Shimbun Publications Inc. About Asahi Japanese Historical Biography

Japanese:

没年：延享4(1747)
生年：延宝6(1678)
江戸中期の和算家。大坂の人。くわしい経歴は不明。関流とは独立に大坂で発展した宅間流の3代目の俊才(初代は大坂の人宅間能清)。建部賢弘の『綴術算経』と同じ享保7(1722)年に『宅間流円理』を著す。この中で鎌田は無限級数を駆使してsinx,arcsinxの展開を定式化したり,円に内接,外接する正244角形の周を計算して円周率を小数点以下25桁ほど求めている。日本の東西でくしくも類似の発見がなされたのは「科学の同時発見」の例としても興味深い。<参考文献>日本学士院編『明治前日本数学史』3巻

(佐藤賢一)

出典　朝日日本歴史人物事典：（株）朝日新聞出版朝日日本歴史人物事典について　情報

<<: Sickle-handled Pseudogobio esocinus

>>: Kamata family