According to Wikipedia, the problem of finding the perimeter of the curve $x^3 = ay^2$ was solved by Wallis and also by Fermat in 1660 by a different method. I'm interested in finding about the method of Fermat and am looking for some reference(s) regarding it.
Any help will be appreciated.
Thanks.
See the Historical Methods section on this page.In this article Fermat's method is illustrated for the curve $y^2=x^3$. https://en.m.wikipedia.org/wiki/Arc_length
There is also a reference to a paper published by Fermat.(It's not in English). Geometric dissertation on curved lines in comparison with straight lines