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posted by  Minnie Mouse on 9/7/2009 1:40:03 PM  |  status: Closed  |  Earned Karma: 160

modular arithmetic problem

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Question Details:
I am given a couple of statements and asked to show the following:
Given:  The GCD IDENTITY says "Given integers a and b (not both zero), there exists integers x and y for which gcd (b,a) = ax+by. 
Given:  If the gcd(a,m) = 1, then the GCD identity (stated above) guarantees that there exists integers u and v such that 1 = au + mv. 
Problem:  Show that in this case, [u] is the multiplicative inverse of [a] in
That's all the information I'm given.  Please explain how I would show this multiplicative inverse.  Thanks!
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Oracle
Karma Points: 30,644
posted by Kingle on 9/7/2009 4:14:31 PM  |  status: Live
Asker's Rating: Lifesaver   
Response Details:
let then    and    also 

now, is the congruent class modulo m so we have

  implies

implies

so we have

which implies that u is the multiplicative inverse of a in










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