A solution to a problem of Fermat, on two numbers of which the sum is a square and the sum of their squares is a biquadrate, inspired by the Illustrious La Grange
Euler returns to the problem, motivated by Lagrange, of finding x and y such that x+y is a square and xx+yy is a fourth power. This is a very short paper.
Original Source Citation
Mémoires de l'académie des sciences de St.-Petersbourg, Volume 10, pp. 3-6.
Opera Omnia Citation
Series 1, Volume 5, pp.77-81.