# Book recommendation on infinitesimal calculus (don't know if thats the right word)

Hey guys, can anyone recommend me a book on infinitesimal calculus. What i mean by infinitesimal calculus is the derivation of differential equations by looking at infinitesimal changes ($$dx\,dt$$, etc...).

Examples of this would be the Black-Scholes PDE, Euler-Bernoulli DE, etc..

I'm an EE student and have a solid background in Math (Calculus I,II & III, etc..), but when my Prof. derived the black-scholes PDE in two slides I couldn't quite follow

Thanks

Or can someone just give me the name of the subject? because i cant seem to find anything under infinitesimal calculus..

I doubt that one book contains all you require but try

Differential Equations with applications and historical notes

by

George F Simmons

In a compact book the author manages a sweep through most areas from traditional right through to modern chaos theory in a very accessible manner.

thanks, will check it out :)