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Math Help - Big O problem

  1. #1
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    Big O problem

    What is the big 0 of (2^n+n^2)(n^3+3^n).

    I get that I foil this out. If I did this correctly, I get that this is O(6^n). Is this right or did I mess up somewhere?
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  2. #2
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    Re: Big O problem

    First, the question is probably what this function is big O of. Second, there are infinitely many answers, and you are probably looking for the slowest-growing one. Then 6^n is correct.
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  3. #3
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    Re: Big O problem

    My apologies. Here is the question: Give a big-O estimate for each of these functions. For the function g in your estimate f(x) is O(g(x)),
    use a simple function g of smallest order.
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  4. #4
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    Re: Big O problem

    Your estimate is still correct.
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  5. #5
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    Re: Big O problem

    The function log(log(n)) grows very, v e r y slowly. If the logs are based 10, it returns 2 for n=10⁰⁰, which is greater than the number of particles in the universe. Nevertheless, this function tends to infinity as n → ∞.

    I am not sure what exactly you difficulty with log(log(n)) is. Feel free to post concrete questions about these functions.
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  6. #6
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    Re: Big O problem

    I tried the problem out. 2n!, 2^2^n,2^n^2, 2^100n, n^4/3 (logn)^2, n^3/2, n(logn)^3/2, nlogn loglogn. How far off am I?
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