# Math Help - Modular arithmetic

1. ## Modular arithmetic

So how does one calculate say 2^9 in the filed F_11( the set of integers of mod11 wrt multiplication)?
Simple , I know but I just cant seem to get it!!!

2. Originally Posted by nicola5
So how does one calculate say 2^9 in the filed F_11( the set of integers of mod11 wrt multiplication)?
Simle , I know but I just cant seem to get it!!!

Well, it's easy to check that 2^5 = -1 (mod 11) , so...

Tonio

3. Originally Posted by nicola5
So how does one calculate say 2^9 in the filed F_11( the set of integers of mod11 wrt multiplication)?
Simle , I know but I just cant seem to get it!!!
The 11 is a prime number so that is and that means that...

(1)

... which is the multiplicative inverse of 2 You will easily find... in is 'interesting' the fact that the same result You arrive also for [among many other examples...] ...

Kind regards

$\chi$ $\sigma$