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I Fermi-dirac integral

  1. Mar 25, 2016 #1
    • Thread closed due to being posted in two forum sections
    i am completely lost. there is an integral in my textbook in fermi dirac statistics whose result is written directly and am not able to understand . it is integral.PNG .
    on expansion by using the method of taylor's series the result should be result.PNG
    where u_f is such that function of u is zero for u greater than uf.
    plz reply as soon as possible. thanks.
  2. jcsd
  3. Mar 25, 2016 #2
    I think this should have been posted in physics thread. Anyways, i will explain here...Assume u is greater than uf....so (u-uf) is so large...
    so in 1+(exp(u-uf)/kT) can be approximated as (exp(u-uf)/kT)

    The reciprocal of this term is (exp-(u-uf)/kT).

    Hope this helps
  4. Mar 26, 2016 #3
    thanks for replying,it helped.
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