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: Where does one term end and the other begin?

  1. Apr 5, 2005 #1
    I need help determining the explicit formula and writing the series in sigma notation with a specified lower limit.

    In both of them, I cannot tell where one term ends and the other begins, or what to do when the sign changes.

    Series #1
    [tex]- 2 - 5 - 8 - 11 - 14 - 17 - 20[/tex]; lower limit = [tex]3[/tex]
    Series #2
    [tex]4.4 + 2.4 + 0.4 - 1.6 - 3.6 - 5.6 - 7.6[/tex]; lower limit = [tex]2[/tex]
  2. jcsd
  3. Apr 6, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Each term is a number, either positive or negative. Since this is a series, you are implicitly adding all the terms. The terms which are negative get rid of the plus sign before them, per convention.

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