# Question on gravitation law derivation

by Thiafon
Tags: derivation, gravitation
 P: 2 Hi, guys. I was wondering on Newton's Gravity Law derivation, and I found this page: http://www.relativitycalculator.com/...vity_Law.shtml Everything seems clear, but the first step is just killing me, because I can't get it. Assuming small incremental changes in s; $$\lim_{t\rightarrow 0} {s} \rightarrow 0$$ we have the following ratios $\frac{\omega}{\nu}$=$\frac{s}{r}$, and $\frac{t}{T}$=$\frac{s}{2πr}$ Could someone help me out? Explain, or just say, which part of math do I have to cover in order to understand that? (btw, I did pre-calculus, and calculus, so concept of limits is familiar to me) Thanks in advance.