Applet to illustrate the epsilon-delta definition of limit

Here’s a GeoGebra applet that I made for my Real Analysis class. It can be used to explore the definition of limit:

Definition. The limit of f(x) as x approaches c is L, or equivalently \displaystyle \lim_{x\to c}f(x)=L, if for any \varepsilon>0 there exists \delta>0 such that whenever 0<|x-c|<\delta, it follows that |f(x)-L|<\varepsilon.