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Math Help - Is it a prime number ??

  1. #1
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    Is it a prime number ??

    Is 2^{30}-1 prime number ? explain ...
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by razemsoft21 View Post
    Is 2^{30}-1 prime number ? explain ...
    Hint: 2^{30} - 1 = (2^{15})^2 - 1^2 = (2^{15} + 1)(2^{15} - 1)
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  3. #3
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    Quote Originally Posted by Jhevon View Post
    Hint: 2^{30} - 1 = (2^{15})^2 - 1^2 = (2^{15} + 1)(2^{15} - 1)
    I know that:
    2^{30} - 1 = (2^{15})^2 - 1^2 = (2^{15} + 1)(2^{15} - 1)
    and
    2^{30} - 1 = (2^{10})^3 - 1^3 = (2^{10} - 1)(2^{20} + 2^{10} + 1)

    sorry, how can I know that this is prime or not ?
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    Like a stone-audioslave ADARSH's Avatar
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    Quote Originally Posted by razemsoft21 View Post
    I know that:
    2^{30} - 1 = (2^{15})^2 - 1^2 = (2^{15} + 1)(2^{15} - 1)
    and
    2^{30} - 1 = (2^{10})^3 - 1^3 = (2^{10} - 1)(2^{20} + 2^{10} + 1)

    sorry, how can I know that this is prime or not ?
    what's a prime number?answer this question to your self.
    If x is a natural number and y is another natural number other than 1

    Can xy be a prime number ??
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  5. #5
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    Quote Originally Posted by ADARSH View Post
    what's a prime number?answer this question to your self.
    If x is a natural number and y is another natural number other than 1

    Can xy be a prime number ??
    since we can factorize it  \Rightarrow it is not prime

    Thanks a lot.
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