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Math Help - modular arith.

  1. #1
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    Question modular arith.

    if we are doing modular arith. why will (a)mod p always have an inverse if p is prime???

    Please help

    Thanks
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  2. #2
    Moo
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    Hello,

    A number a has an inverse modulo p if a is coprime with p.

    so if a \neq p^n, where p is prime, then a has an inverse modulo p !
    especially if a<p, then it has an inverse.
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  3. #3
    Senior Member JaneBennet's Avatar
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    Quote Originally Posted by Moo View Post
    Hello,

    A number a has an inverse modulo p if a is coprime with p.

    so if a \neq \color{red}np, where p is prime, then a has an inverse modulo p !
    especially if a<p, then it has an inverse.
    Just a minor correction.
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