1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Help with limit expression

  1. Nov 1, 2005 #1


    User Avatar
    Gold Member

    Is it correct to think about the expresion:
    "the limit of f(x) is b when x->a" as saying that for every x thats very close to a but not a (in the deleted neighborhood of a) there is a f(x) thats very close to b (in the neibourhood of b) - or is that not precise enough?
  2. jcsd
  3. Nov 1, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper

    It's definately not precise enough for a mathematical definition. What do you mean by 'very close to a'. What is 'very close'?
    The idea of [itex]\lim_{x\to a}f(x)=b[/itex] is that you can make f(x) as close as you want to b by choosing x close enough (but not equal to) a. By close I mean that the distance |f(x)-b| can be made as small as we want. How small? Smaller than any given positive number.

  4. Nov 1, 2005 #3
    Might want to use 'gets closer' instead of 'is close to'

    Thats pretty much the epsilon delta method.
  5. Nov 1, 2005 #4


    User Avatar
    Gold Member

    Thanks guys for making that clear.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?