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IHateMayonnaise
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Homework Statement
Part of a much bigger problem, but I am hung up on solving the following:
[tex]ln\left [ \left(\frac{N+n}{2}\right ) ! \right ] = \left ( \frac{N+n+1}{2}\right) \frac{ln(N+n)}{2}\right )[/tex]
I am trying to follow a proof in http://books.google.com/books?id=CD...on random walk&pg=PA205#v=onepage&q=&f=false" My confusion comes from eqn. 10.34. Clearly this is following the Stirling Approximation, where the associated substituted approximation is eqn. 10.33.
Homework Equations
The stirling approximation (Eqn. 10.33), as well as Eqns. 10.31 and 10.32.
The Attempt at a Solution
In trying to reduce the following:
[tex]ln\left [ \left(\frac{N+n}{2}\right ) ! \right ] [/tex]
I do not understand how I am to use the stirling approximation since it specifies the definition of [tex]ln(n!)[/tex], and not what I have above. Is there some identity that I am not remembering? I know that:
[tex]ln\left [ \left(\frac{N+n}{2}\right ) ! \right ] [/tex]
is NOT the same as
[tex]ln\left [ \frac{(N+n)!}{2!} \right ] [/tex]
But other than that I cannot remember a relevant identity. Thoughts?
IHateMayonnaise
EDIT: To solve use the Stirling's approximation twice. Nevermind :)
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