This preview shows page 1. Sign up to view the full content.
Unformatted text preview: Show that the usual formula yields the inverse of A .] c. Conclude that A M 2 ( R ) if and only if det( A ) R . Exercise 3. Given that Z n = U ( n ) for n 2, prove that Z n = Z n { } if and only if n is prime. This completes the proof that Z n is a eld if and only if n is prime. Exercise 4. Let A = 1 32 4 . Determine if A is a unit in M 2 ( R ) for the following choices of R . a. R = Q b. R = Z c. R = Z n (your answer will depend on n )...
View
Full
Document
This note was uploaded on 02/29/2012 for the course MATH 3362 taught by Professor Ryandaileda during the Spring '10 term at Trinity University.
 Spring '10
 RyanDaileda
 Algebra

Click to edit the document details