1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Proving Stirling's formula help

  1. Nov 26, 2004 #1
    proving Stirling's formula.. help plz

    How can I prove Stirling's formula?

    n!= integral from 0 to inf. exp(-t) t^n dt= n^n exp(-n) (2 pi n)^0.5

    there's a hint to use the substitution t=ny & ln(1+y) = y- 0.5 y^2

    I tried to use it but I couldn't intgrate.. I tried integrating by parts but it became more complicated.. :frown:

    Can anyone help?

    (How can I write the mathematical symbols here?)

    Thanks
     
    Last edited: Nov 26, 2004
  2. jcsd
  3. Nov 26, 2004 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Try:
    http://www.sosmath.com/calculus/sequence/stirling/stirling.html

    AM
     
  4. Nov 26, 2004 #3

    Tide

    User Avatar
    Science Advisor
    Homework Helper

    Another approach would be to use the method of steepest descent. Basically, you can find where [itex]t^n e^{-t}[/itex] is a maximum and observe that the most significant contribution to the integral comes from near that maximum.
     
  5. Nov 27, 2004 #4
    Thanks for helping.. but I should uuse the substitution t=ny..

    HELP PLZ
     
  6. Dec 3, 2004 #5

    NateTG

    User Avatar
    Science Advisor
    Homework Helper

  7. Dec 3, 2004 #6
    Thanks alot..
     
  8. Jan 5, 2012 #7
    Re: proving Stirling's formula.. help plz

    How can I find equivalent Frenkel defects in the crystal through the equivalent Stralink
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Similar Discussions: Proving Stirling's formula help
  1. Prove of formula (Replies: 4)

  2. Help with formula (Replies: 1)

Loading...