Computing Kth Roots Modulo M

bigp0ppa1046

New member
Joined
Jan 30, 2007
Messages
18
Our method for solving x^k=b (mod m) is to first find integers u and v satisfying ku-Φ(m)v=1, and then the solution is x=b^u (mod m). However, we only showed that this works provided that gcd(b,m)=1, since we used Euler's formula b^ Φ(m)=1 (mod m).

a)If m is a product of distinct primes, show that x=b^u (mod m) is always a solution to x^k=b (mod m), even if gcd(b,m)>1.

b) Show that our method does not work for the congruence x^5= 6 (mod 9).

= sign means "congruent to"
 
Top