How to prove (p-1) = -1 (mod p), p is a prime.

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In summary, to prove that (p-1) = -1 (mod p) for a prime number p, we can use the fact that for any integer a, a = a (mod p) for a prime number p. This result, known as Wilson's theorem, is significant in number theory and cryptography, and can be used to prove the primality of a number and in the RSA encryption algorithm. One example of how to prove this for a specific prime number is 7, where (7-1) = 6 = -1 (mod 7). It is not possible to prove this for a non-prime number, as it is based on the properties of prime numbers. Another method to prove this is using
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lifom
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(p-1)! = -1(mod p), where p is a prime
I have tried small values of p but I can't find any pattern. Can anyone give me some hints or directions? I don't know a detail proof. Thank you
 
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The matter turns on inverses. For every a in the system there is an a^-1, such that a*a^-1 = 1. (Generally that is an axiom of the group property.)
 

Related to How to prove (p-1) = -1 (mod p), p is a prime.

1. How do you prove that (p-1) = -1 (mod p) for a prime number p?

To prove that (p-1) = -1 (mod p), we can use the fact that for any integer a, a = a (mod p) for a prime number p. Therefore, we can rewrite (p-1) as (p-1) = (p-1) (mod p), and since (p-1) mod p is equivalent to -1 mod p, we can conclude that (p-1) = -1 (mod p).

2. What is the significance of proving (p-1) = -1 (mod p) for a prime number p?

Proving (p-1) = -1 (mod p) is important in number theory and cryptography. This result is known as Wilson's theorem and can be used to prove the primality of a number. It is also used in the RSA encryption algorithm, which is widely used in secure communication systems.

3. Can you give an example of how to prove (p-1) = -1 (mod p) for a specific prime number p?

Let's take the prime number 7 as an example. We know that 7 is a prime number and therefore, according to Wilson's theorem, (7-1) = 6 = -1 (mod 7). This can be verified by dividing 6 by 7, which gives a remainder of -1. Therefore, (7-1) = -1 (mod 7).

4. Is it possible to prove (p-1) = -1 (mod p) for a non-prime number p?

No, it is not possible to prove (p-1) = -1 (mod p) for a non-prime number p. This result is only applicable for prime numbers as it is based on the properties of prime numbers. If p is not a prime number, then the statement (p-1) = -1 (mod p) may not hold true.

5. Can you use a different method to prove (p-1) = -1 (mod p) for a prime number p?

Yes, there are multiple ways to prove (p-1) = -1 (mod p) for a prime number p. One method is to use Fermat's little theorem, which states that for any prime number p, a^(p-1) = 1 (mod p) for all integers a. By substituting a = -1, we get (-1)^(p-1) = 1 (mod p). But since p is an odd prime number, (-1)^(p-1) = -1 (mod p), which proves that (p-1) = -1 (mod p).

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