Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Limit question

  1. Sep 26, 2006 #1
    I have a question:

    what is lim (n--->infinity)= 1/(3+(-1)^n))? My opinion that this limit does not exist.
  2. jcsd
  3. Sep 26, 2006 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    "Do not opine, PROVE!"

    Apocryphal quote from Euclid. :smile:
  4. Sep 26, 2006 #3


    User Avatar
    Science Advisor
    Homework Helper

    Are you asking about
    perhaps? The equals sign in your post is confusing me. If so, are you familiar with the lim sup and lim inf? That would give you an easy direct proof: if lim sup = lim inf, that's the limit; otherwise, the limit does not exist.
  5. Sep 26, 2006 #4
    i have dealt with sup but not with inf but i will look them up. Thx anyway.
  6. Oct 1, 2006 #5

    if n∈Z (Z=Integer) then we have two answer for equation

    1) if n=Even then answer=1/4

    2) if n=Odd then answer=1/2

    if n∈R (R=Real) then equation is undefined

    for example: (-1)^1/2 does not exist.:smile:
  7. Oct 1, 2006 #6
    It certainly does, it just isn't real.
  8. Oct 2, 2006 #7
  9. Oct 2, 2006 #8
    thank you for help me
  10. Oct 3, 2006 #9
    thank you for conduce:tongue:

    Accordingly this sequence isn't convergent:smile:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Limit question
  1. Limit question (Replies: 2)

  2. Limit question (Replies: 3)

  3. Limit question (Replies: 9)

  4. Limit question (Replies: 1)

  5. A limit question (Replies: 7)