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Finding the value of n in nlog(n)

  1. Sep 11, 2010 #1


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

    Pretty simply, if you have an inequality like c1*n^2<c2*n*log(n), how do you find the values of n for this without plugging in diifferent values and substituting? Or a question like nlog(n)=k where k is a constant.

    2. Relevant equations
    Umm...thats it.

    3. The attempt at a solution
    I just plugged in solutions or thought I'd use MATLAB or something. This isn't actually my homework, but it comes up a lot in complexity questions, and I need to know hot to solve it.
  2. jcsd
  3. Sep 11, 2010 #2
    There is no analytic way to solve the above question. But you could ballpark the answer by drawing graphs. nlog(n) = k => log(n) = 1/n. Draw both graphs and find out the answer.

    Or you could solve this problem using the Lambert W function, which is about as close you can get to an analytic solution.

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