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Homework Help: Big Oh help

  1. Jan 18, 2012 #1
    1. The problem statement, all variables and given/known data

    If f1= x and f2 = y show that f1 = O(f) and f2 = O(f) where f(x,y) = (x2 + y2)1/2


    2. Relevant equations

    I have the solution to this question, but I don't understand how it arrives there. I'm currently revising for a masters, but I've forgotten loads. :(


    3. The attempt at a solution

    Since x/√(x2 + y2) ≤ 1, y/√(x2 + y2) ≤ 1 it follows that fk = O(k), k =1, 2
     
  2. jcsd
  3. Jan 18, 2012 #2

    lanedance

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    Homework Helper

    big Oh means it's bounded by constant, ie
    |f1|<=M|f|
    for some M, usually as x gets big

    As you have multiple variables, it will be as the magnitude of the vector gets big

    I'm not sure what you mean by f(k)=O(k)?
     
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