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Homework Help: Evaluate the sum of infinite series.

  1. Mar 27, 2012 #1
    1. The problem statement, all variables and given/known data
    If possible, evaluate the sum :
    http://www4a.wolframalpha.com/Calculate/MSP/MSP31841a0i89gaa1b8f5c80000373e40eh779f93h7?MSPStoreType=image/gif&s=17&w=109&h=47 [Broken]

    2. Relevant equations

    3. The attempt at a solution
    Not really sure what to do. I've tried writing out the terms but its not a geometric series so it didn't help. The only way I can think of is when writing out the first few terms I get something close the the correct answer, which is 0.9659... the numbers get so close together becuase its an alternating series that only the first few terms really matter... but this obviously isnt an accurate way or correct way to do the problem.
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Mar 27, 2012 #2


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    It looks an awful lot like a Taylor series for the cosine function to me.
  4. Mar 27, 2012 #3
    ahh your right lol... its just cos(pi/12). Thanks!
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