1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: What is this?

  1. Apr 2, 2008 #1
    I have no math training beyond high school 45 years ago, and I don’t remember much of it. However I am doing a project, and I find the series below is quite valuable. But I do not know what it is or what it is called. It is like this:

    X + 1 (1/x + 1/x^2 + 1/x^3 . . . ).

    It comes ever closer to a value which is very significant in what I am doing. I wonder if someone can tell me what this is called, and what it can be used for.
  2. jcsd
  3. Apr 2, 2008 #2


    User Avatar
    Homework Helper

    Well what is in the brackets is a geometric progrssion
  4. Apr 2, 2008 #3


    User Avatar
    Science Advisor

    Yes, the part in parentheses is a geometric series that can be summed (provided the absolute value of x is bigger than 1):

    1/x + 1/x^2 + 1/x^3 + ... = 1/(x-1)
  5. Apr 3, 2008 #4
    Thank you!
  6. Apr 3, 2008 #5


    User Avatar
    Homework Helper

    For that sum to converge,

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook