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Homework Help: An integral

  1. Jul 14, 2010 #1
    1. The problem statement, all variables and given/known data

    How to integral this one?

    1/(1+a*cosx)



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jul 14, 2010 #2
    In this case, you use wolframalpha.com because the calculation by hand is brutal.

    http://www.wolframalpha.com/input/?i=integrate+(1%2Ba*cos(x))^-1

    Some people think that's cheating, but I think doing the grunt work here would be a waste of time since there's no new insight. From the looks of it, it's just several cumbersome integration by parts with the inverse hyperbolic tangent function.
     
  4. Jul 15, 2010 #3

    hunt_mat

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    Homework Helper

    I would try [tex]t=\tan (\theta /2)[/tex], it's one of the standard ones.
     
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