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Homework Help: Getting n alone in n!=x and nlgn=x

  1. Sep 10, 2009 #1
    1. The problem statement, all variables and given/known data

    I need to know the greatest n for which n! is greater or equal to x, and the greatest n for which nlgn is greater or equal to x.

    2. Relevant equations

    Can't think of any. Sorry!

    3. The attempt at a solution

    For a "normal" function, like, say, lgn or n^2, it would be as easy as inverting the function and getting n on its own, like this:

    lgn = x
    n = 2^x (where lg is of base 2)


    n^2 = x
    n = sqrt(x).

    However, for n!=x and nlgn=x I can't come up with a way to do this. Help!
  2. jcsd
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