Proposition 5.5.29. Let n >1 be an integer, and let a be an element of Zn \ {0}. Then a has an inverse in Zn if and only if gcd(a, n)=1 (that is, a is relatively prime to n). The proof of this proposition is up to you:

Elements Of Modern Algebra
8th Edition
ISBN:9781285463230
Author:Gilbert, Linda, Jimmie
Publisher:Gilbert, Linda, Jimmie
Chapter6: More On Rings
Section6.3: The Characteristic Of A Ring
Problem 13E
icon
Related questions
Question

Please show step by step

Proposition 5.5.29. Let n >1 be an integer, and let a be an element of
Zn \ {0}. Then a has an inverse in Zn if and only if gcd(a, n)=1 (that is, a
is relatively prime to n).
The proof of this proposition is up to you:
Transcribed Image Text:Proposition 5.5.29. Let n >1 be an integer, and let a be an element of Zn \ {0}. Then a has an inverse in Zn if and only if gcd(a, n)=1 (that is, a is relatively prime to n). The proof of this proposition is up to you:
Exercise 5.5.30. Let n > 1 be an integer, and let a be an element of
Z, \ {0}.
(a) Prove the "only if" part of Proposition 5.5.29. That is, prove that if a
has an inverse in Z, \ {0} then gcd(a, n)=1. (*Hint*)
5.5 MODULAR DIVISION
147
(b) Prove the "if" part of Proposition 5.5.29. That is, prove that if gcd(a, n)=1
then a has an inverse in Z, \ {0} . (*Hint*)
Transcribed Image Text:Exercise 5.5.30. Let n > 1 be an integer, and let a be an element of Z, \ {0}. (a) Prove the "only if" part of Proposition 5.5.29. That is, prove that if a has an inverse in Z, \ {0} then gcd(a, n)=1. (*Hint*) 5.5 MODULAR DIVISION 147 (b) Prove the "if" part of Proposition 5.5.29. That is, prove that if gcd(a, n)=1 then a has an inverse in Z, \ {0} . (*Hint*)
Expert Solution
Step 1

Advanced Math homework question answer, step 1, image 1

steps

Step by step

Solved in 3 steps with 3 images

Blurred answer
Recommended textbooks for you
Elements Of Modern Algebra
Elements Of Modern Algebra
Algebra
ISBN:
9781285463230
Author:
Gilbert, Linda, Jimmie
Publisher:
Cengage Learning,
Linear Algebra: A Modern Introduction
Linear Algebra: A Modern Introduction
Algebra
ISBN:
9781285463247
Author:
David Poole
Publisher:
Cengage Learning