Person: Ajima, Chokuyen Naonobu
Naonobu Ajima was a Japanese mathematician and astronomer who developed a theory of integration.
Mathematical Profile (Excerpt):
- Ajima was over thirty years of age before he began his studies with Yamaji.
- While studying with him, Ajima wrote books on astronomy and helped his teacher to compile an almanac.
- It was only after Yamaji's death that Ajima began to write works on mathematics.
- The book had a preface written in 1799, one year after Ajima's death, by Kasawa Makoto, one of his students.
- Kasawa was a fine mathematician and he succeeded Ajima as a master of the Seki school.
- He was certainly not Ajima's only star pupil for there were also excellent mathematicians such as Masatoda Baba and Hiroyasu Sakabe who continued the tradition of the Seki school.
- Ajima's work went towards geometry despite the strong algebraic numerical tradition in the Seki school.
- Ajima refined the method subdividing the chord of an arc into equal small segments, so producing a method similar to that of the definite integral.
- Immediately after developing this method of integration, Ajima developed a method for computing volumes by double integration.
- This book introduced logarithms into Japan and it is clear that Ajima had read the work since he uses some of the same notation in his own work on logarithms.
- Let us look at two particular problems solved by Ajima.
- Although his solution was unpublished, nevertheless Ajima became famous for his work on this problem.
- Ajima's remarkable achievement was to reduce this to an equation of degree 10.
- A year after this fine achievement, Ajima was promoted to hold the position of "gun bugyou" or "country magistrate".
- It is today called the Malfatti Problem since it was posed in 1803 by Gian Francesco Malfatti, but Ajima's contributions were made around 30 years earlier.
- It is precisely the problem of maximising the area of the three mutually tangent circles that Ajima solved in Fukyu sampo.
- This, of course, is not relevant to Ajima's problem which is only posed in terms of maximising the area of three non-overlapping mutually tangent circles.
- After Ajima's death, he was buried in the Jorin-jo Temple, Mita, Tokyo, and his grave can still be visited today.
Born 1732, Shiba, Edo (now Tokyo), Japan. Died 14 November 1798, Shiba, Edo, Japan.
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Tags relevant for this person:
Astronomy, Origin Japan
Thank you to the contributors under CC BY-SA 4.0!
Adapted from other CC BY-SA 4.0 Sources:
- O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive