Uniqueness of integers question

Click For Summary

Homework Help Overview

The problem involves finding integers s and t such that 1 = 7*s + 11*t, and demonstrating that these integers are not unique. The context relates to number theory and the properties of integers, particularly in relation to linear combinations of relatively prime numbers.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the existence of integers that satisfy the equation and question the rigor of the provided examples. There is mention of a theorem regarding relatively prime integers and the implications for the uniqueness of solutions.

Discussion Status

The discussion includes attempts to clarify the theorem related to linear combinations of integers and the uniqueness of solutions. Some participants affirm the correctness of the examples given, while others explore the generality of the theorem without reaching a consensus on the proof of uniqueness.

Contextual Notes

Some participants express uncertainty about the rigor of their approaches and the need for a more formal proof regarding the non-uniqueness of the solutions.

BustedBreaks
Messages
62
Reaction score
0
Find integers s and t such that 1 = 7*s + 11*t. Show that s and t are not unique.

I can find numbers that satisfy this question, t=2, s=-3 and t=-5, s=8, that show s and t are not unique, but this doesn't seem to be rigorous and I'm not sure where to start with proving this.
 
Physics news on Phys.org
In general there is a theorem which states that for any two relatively prime positive integers a and b there exist integers x and y such that: 1=ax+by. Or, a and b are relatively prime iff there exist integers x and y such that 1=ax+by.
 
sutupidmath said:
In general there is a theorem which states that for any two relatively prime positive integers a and b there exist integers x and y such that: 1=ax+by. Or, a and b are relatively prime iff there exist integers x and y such that 1=ax+by.

yea.. or there exist integers x and y such that (a,b)=ax+by.
 
icystrike said:
yea.. or there exist integers x and y such that (a,b)=ax+by.

THis is an even more general result. Namely if L={n|n=ax+by, x,y in Z}, then the smallest element of L is gcd(a,b).
 
BustedBreaks said:
Find integers s and t such that 1 = 7*s + 11*t. Show that s and t are not unique.

I can find numbers that satisfy this question, t=2, s=-3 and t=-5, s=8, that show s and t are not unique, but this doesn't seem to be rigorous and I'm not sure where to start with proving this.
But this is completely correct and a perfectly good solution to this problem. 7(-3)+ 11(2)= -21+ 22= 1, 7(8)+ 11(-5)= 56- 55= 1, and these are two distinct solutions. That is all that is necessary to show that the solution to this particular problem is not unique.
 

Similar threads

  • · Replies 16 ·
Replies
16
Views
3K
Replies
9
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
Replies
27
Views
4K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
4
Views
4K
Replies
3
Views
2K
  • · Replies 19 ·
Replies
19
Views
3K
Replies
9
Views
3K