Pell Equations

``Re: L'Hopital and Bernoulli'' by rspuzio on 2005-12-02 14:12:03 As a general rule, most attributions in mathematics need to be taken with a grain of salt --- names commonly used to designate theorems, functions, spaces, and what not need to be understood simply as convenient conventional designations and _not_ as having historical weight. As another example, one might take the Pell equation, which was already familiar to Fermat two centuries before Pell and studied by Brahmagupta a millennium before either Fermat or Pell. From: http://planetmath.org/?op=getmsg&id=9034 From: http://mathworld.wolfram.com/PellEquation.html While Fermat deserves credit for being the first to extensively study the equation, the erroneous attribution to Pell was perpetrated by none other than Euler himself (Nagell 1951, p. 197; Burton 1989; Dickson 2005, p. 341). The Pell equation was also solved by the Indian mathematician Bhaskara. Pell equations are extremely important in number theory, and arise in the investigation of numbers which are figurate in more than one way, for example, simultaneously square and triangular. Eric W. Weisstein