I have read Spivak's Calculus up to chapter 5, which is on Limits. Up until this point, the majority has been very straightforward and easy to understand. However, I am having trouble grasping the concept of limits in the style/method that Spivak describes them. Can anyone elaborate in a more general sense this definition that he has laid out, possibly with an example? "The function f approaches the limit l near a means: for every ε > 0 there is some δ > 0 such that, for all x, if 0 < |x - a| < δ, then |f(x) - l < ε."