Euler's definition of the derivative

Harold M. Edwards
2007 Bulletin of the American Mathematical Society  
Euler's method of defining the derivative of a function is not a failed effort to describe a limit. Rather, it calls for rewriting the difference quotient in a way that remains meaningful when the denominator is zero.
doi:10.1090/s0273-0979-07-01174-3 fatcat:ndz6d5lfp5aafb3nlvaea2e6ja