Homepage Solution manuals Ivan Niven An Introduction to the Theory of Numbers Exercise 1.2.7 (Relatively prime and relatively prime by pairs)

Exercise 1.2.7 (Relatively prime and relatively prime by pairs)

Exhibit three integers that are relatively prime but not relatively prime in pairs.

Answers

Proof. 6 = 2 × 3 , 10 = 2 × 5 , 15 = 3 × 5 is such an example.

Then

gcd ( 6 , 10 , 15 ) = 1

(see Exercise 1.2.3(e) : 14 × 6 + 7 × 10 + 1 × 15 = 1 ), but

gcd ( 6 , 10 ) = 2 , gcd ( 6 , 15 ) = 3 , gcd ( 10 , 15 ) = 5 .

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2024-06-16 11:05
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