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Math Help - Discrete math question about sets.

  1. #1
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    Discrete math question about sets.

    little confused as to what this is asking:

    Let P be the set of primes and define a relation R from P to N (the natural numbers) by pRn if and only if p|n.

    Find all the primes p such that pR126.
    Find all n such that 3Rn.
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  2. #2
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    Quote Originally Posted by thecleric View Post
    Let P be the set of primes and define a relation R from P to N (the natural numbers) by pRn if and only if p|n.
    Find all the primes p such that pR126.
    Find all n such that 3Rn.
    List all prime numbers p \le \sqrt{126}.
    Which of those divide 126?
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  3. #3
    Super Member Gamma's Avatar
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    alternatively write out the prime factor decomposition for 126.
    126=2*3^2*7 so looks like 2, 3, 7

    For the second one its just all natural numbers of the form 3n
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