# I Two questions on Newton Fluxions

1. Dec 21, 2016

### jonjacson

Hi folks,

I have two questions:

1.- I am reading his Method of fluxions and when he writes x with a dot over the letter, Does he mean the differential of x, or what we say dx? In other words, Is that an infinitesimal quantity "smaller than any other fixed number"?

I ask because I have read in some web pages that x dot meant dx/dt.

2.- In the entire Principia it is posible to find a geometric representation of ininitesimal quantities, Is there any math book dedicated exclusively to explain how to represent graphically differentials on geometric figures?

Thanks!!!!!!!

2. Dec 21, 2016

### Simon Bridge

1. in Newton's notation, a dot over a letter refers to the time derivative while a primed letter refers to the space derivative in 1D.
However, you will have to quote the passage to be sure.

2. An introductory college-level work on calculus will usually cover it, or, at least, the tools needed to construct one.