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Homework Help: Help with asymptotic expansions, please

  1. Sep 26, 2010 #1
    Help with asymptotic expansions, please!!

    1. The problem statement, all variables and given/known data

    What is the behavior of asymptotic expansion of cosine integral function? Under what conditions should it be valid approximation to Ci(x)


    Ci(x)=- ∫∞x (cost/t)dt {in words} (Integral from x to infinity)(cost/t)dt


    2. Relevant equations

    -Intefral x to infinty(e^it/t)dt

    3. The attempt at a solution
    I have integrated the functions by part, i got the right answer with the right asymptotic expansion i.e. Ci(x) = (sinx/x)-(cosx/x)-(1.2sinx/x)+(1.2.3cosx/x^4)+R
     
  2. jcsd
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