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

Please help

Thanks(Headbang)

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- Mar 8th 2009, 08:30 AMmandy123modular arith.
if we are doing modular arith. why will (a)mod p always have an inverse if p is prime???

Please help

Thanks(Headbang) - Mar 8th 2009, 11:48 AMMoo
Hello,

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

so if $\displaystyle a \neq p^n$, where p is prime, then a has an inverse modulo p !

especially if $\displaystyle a<p$, then it has an inverse. - Mar 9th 2009, 04:57 AMJaneBennet