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Series Maths

  1. Dec 10, 2011 #1
    1. The problem statement, all variables and given/known data


    http://puu.sh/ajGv [Broken]


    2. Relevant equations

    ??


    3. The attempt at a solution

    Q1- is -3, -1 and 1
    Q2- CD is 2
    Q3- I dont understand hence cant even start it
     
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Dec 10, 2011 #2

    Mentallic

    User Avatar
    Homework Helper

    That expression just means what is the sum of 2r-5 from r=1 up to n. So, what is

    (2(1)-5)+(2(2)-5)+(2(3)-5)+...+(2(n)-5)

    You should have been given a formula to calculate the sum of an arithmetic series.
     
  4. Dec 10, 2011 #3
    use the following:


    arithmetic%20sum%20formula1.gif
     
  5. Dec 10, 2011 #4
    Did you reach your answer yet?
     
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