How can I prove that gcd(a,b) is an integer and gcd(a/b, b/h) = 1?

In summary, the conversation discusses the proof of a question regarding the greatest common divisor of two integers. The first part of the question asks whether certain statements are true, while the second part examines the definition of the greatest common divisor and its relation to the given integers. The theorem given in "Elementary Number Theory" by Dudley confirms the truth of the second statement.
  • #1
simo1
29
0
can I get hints on how to prove this question:

let a,b be in Z(integer) with h=gcd(a,b) not equal to zero then [(a divide b), (b divide h)] are in Z. and gcd[ (a divide h, b divide h)]=1
 
Mathematics news on Phys.org
  • #2
Did you mean "a divide h"? The first part is pretty much the definition of the greatest common divisor ("the greatest integer which divides both numbers", so trivially $h$ divides both $a$ and $b$). What definition of the gcd are you working from? For the second part, suppose that $a/h$ and $b/h$ shared a common factor, so that their gcd was not equal to $1$. Would that not conflict with the definition of $h = \gcd(a, b)$? Can you see the problem?
 
  • #3
Let me restate the problem to see if I understand it correctly.


Given that a,b are integers, h=gcd(a,b) and h not equal to 0 then
is it true that:
  1. a divided by b and b divided by h are integers
  2. gcd(a divided by h, b divided by h)=1


Statement 2 is true and is given as Theorem 1 in "Elementary Number Theory" by Dudley.

In Statement 1, there is no reason why a divided by b should be an integer.
 
Last edited:

What is the Greatest Common Divisor (GCD)?

The Greatest Common Divisor (GCD) is the largest positive integer that divides two or more integers without leaving a remainder.

How is the Greatest Common Divisor (GCD) calculated?

The GCD can be calculated using various methods, including prime factorization, Euclid's algorithm, and the binary GCD algorithm.

What are some real-life applications of the Greatest Common Divisor (GCD)?

The GCD is used in many fields, including computer science, engineering, and cryptography. It is used to simplify fractions, find the lowest common denominator, and solve problems involving ratios and proportions.

Can the Greatest Common Divisor (GCD) be greater than the smallest of the two numbers?

Yes, the GCD can be greater than the smallest of the two numbers. This occurs when the smallest number is a factor of the larger number.

What is the relationship between the Greatest Common Divisor (GCD) and the Least Common Multiple (LCM)?

The GCD and LCM are related through the fundamental theorem of arithmetic, which states that any positive integer can be expressed as a unique product of prime numbers. The GCD is the largest common factor of two or more numbers, while the LCM is the smallest positive integer that is divisible by all of the numbers in a given set.

Similar threads

Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
2
Views
959
  • Precalculus Mathematics Homework Help
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
Replies
5
Views
2K
  • Precalculus Mathematics Homework Help
Replies
2
Views
971
  • Precalculus Mathematics Homework Help
Replies
1
Views
756
Replies
4
Views
2K
  • General Math
Replies
1
Views
1K
Back
Top