Let p and n be integers. Prove that, if p is prime, then gcd(p, n) = p or gcd(p, n) = 1. . .
(i.) Using proof by contrapositive
(ii.) Using proof by contradiction
Let p and n be integers. Prove that, if p is prime, then gcd(p, n) =...
1) Let n and m be positive integers. Prove: If nm is not divisible by an integer k, then neither n norm is divisible by k. Prove by proving the contrapositive of the statement. Contrapositive of the statement:_ Proof: Direct proof of the contrapositive
(i) For every nonzero integers a, b, prove that gcd(a, b) = gcd(−a, b). (ii) Show that for every nonzero integers a, b, a, b are relatively prime if and only if a and −b are relatively prime.
8. (a) Prove that if p and q are prime numbers then p2 + pq is not a perfect square. (b) Prove that, for every integer a and every prime p, if p | a then ged(a,pb) = god(a,b). Is the converse of this statement true? Explain why or why not. (c) Prove that, for every non-zero integer n, the sum of all (positive or negative) divisors of n is equal to zero. 9. Let a and b be integers...
Assignment 6 1. Prove by contradiction that: there are no integers a and b for which 18a+6b = 1. 2. Prove by contradiction that: if a,b ∈ Z, then a2 −4b ≠ 2 3. Prove by contrapositive that: If x and y are two integers whose product is even, then at least one of the two must be even. Make sure that you clearly state the contrapositive of the above statement at the beginning of your proof. 4. Prove that...
Let p be a prime number. Prove that if there exists a solution to the congruence c(mod p), then there exist integers m, n such that p = m2 + 2n2. Hint. Make a careful study of the proof of Fermat's Two Square Theorem, and then try to modify that proof (or at least some portion of it) to come up with a proof of this statement. Toward the end of the proof, the following observation can be helpful: If...
1. Consider the following claim. Claim: For two integers a and b, if a + b is odd then a is odd or b is odd. (a) If we consider the claim as the implication P =⇒ Q, which statement is P and which is Q? (b) Write the negations ¬P and ¬Q. (c) (1 point) Write the contrapositive of the claim. (d) Prove the contrapositive of the claim. 2. Use contraposition (proof by contrapositive )to prove the following claim....
Let p be a prime with p ≥ 13. Prove that among the integers 2,11 and 22, either all three are quadratic residues modulo p or exactly one is a quadratic residue modulo p.
Let q be a prime and let m and n be non-zero integers. Prove that if m and n are coprime and q? divides mn, then q? divides m or q? divides n
Let p be a prime. Consider the sequence 11,22,3, 44,55 modulo p. Prove that the resulting sequence is periodic with smallest period p(p - 1). (This means that p(p - 1) is the least among all positive integers l with the property that whenever n = m (mod l), we have n" = m" (mod p).) Let p be a prime. Consider the sequence 11,22,3, 44,55 modulo p. Prove that the resulting sequence is periodic with smallest period p(p -...
Let J be the ring of integers, p a prime number, and () the ideal of J consisting of all multiples of p. Prove (a) J@) is isomorphic to Jp, the ring of integers mod p. (b) Using Theorem 3.5.1 and part (a) of this problem, that J, is a field.