送交者: HunHunSheng 于 2006-6-28, 09:55:58:
I found most math text books in USA, even for enginnerring do not cover that. They simply use
intuitive way to define it. If limf(x) as x->0 is
A, then they define the limit A as a number f(x) will apporach. Not that given any however small number epsilon, then there exist a number delta as long as
|x-0| is small than delta, |f(x)-A| will be smaller than
epsilon