Standard part function: Difference between revisions

Revision as of 11:32, 4 May 2011

Revision as of 20:40, 21 May 2011

Line 1:

[[Image:Gottfried Wilhelm von Leibniz.jpg|thumb|200px|right|''[[Gottfried Wilhelm Leibniz]]'' Inventor of [[infinitesimal calculus]] ]]

In [[non-standard analysis]], the '''standard part function''' "st" is a mathematical implementation of [[Pierre de Fermat]]'s [[adequality]]. It is the key ingredient in [[Abraham Robinson]]'s formalisation (the more usual formalisation is via [[(ε, δ)-definition of limit]]) of Leibniz's informal definition (see [[ghosts of departed quantities]]) of the derivative as the ratio of two infinitesimals

:<math>\frac{dy}{dx}</math>,

see more at [[non-standard calculus]].