E739 -- Regula facilis problemata Diophantea per numeros integros expedite resolvendi
(An easy rule for Diophantine problems which are to be resolved quickly by integral numbers)
Summary:
Euler returns to the problem of making formulas of the form axx + bx
+ g into squares. He generalizes to try to find a and b solving
axx + bx + g =
zyy + hy + t.
Again, it seems to rely on an initial solution and a clever application of solutions to Pell’s equation. He does some nice examples:
- To find all triagonal numbers that, at the same time, are squares.
- To find all square numbers that, diminshed by one, are triangular numbers. Some such squares are 1, 4, 16, etc.
- To find those triangular numbers that, tripled, are again triangular numbers, such as 1, whose triple is exactly a triangular number.
According to the records, it was presented to the St.
Petersburg Academy on May 4, 1778.
Publication:
-
Originally published in Memoires de l'academie des sciences de St.-Petersbourg 4, 1813, pp. 3-17
-
Opera Omnia: Series 1, Volume 4, pp. 406 - 417
- Reprinted in Commentat. arithm. 2, 1849, pp. 263-269 [E739a]
Documents Available:
- Original publication: E739
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