Finding inverse function for a mapping with a congruent class
Problem:
F([X]7)=[2x]7
Find the inverse for this function.
So this function maps from x(mod 7) to 2x(mod 7). I was able to prove that the function is one-to-one and onto in a previous function, but I am lost after that.
Am I looking for a function that produces [1]7 when multiplied with [2x]7?
I really would appreciate any and all help.
Re: Finding inverse function for a mapping with a congruent class
No, there is no multiplication involved here. You are, as the problem says, looking for the inverse function.
It's not at all difficult to write out exactly what f is:
f(0)= 0, f(1)= 2, f(2)= 4, f(3)= 6, f(4)= 1, f(5)= 3, f(6)= 5.
Therefore, = 0)
, = 4)
, = 1)
, etc.
Re: Finding inverse function for a mapping with a congruent class
Re: Finding inverse function for a mapping with a congruent class
Quote:
Originally Posted by
alexmahone 
This is correct, but how did you go from )
to )
?
Re: Finding inverse function for a mapping with a congruent class
Quote:
Originally Posted by
hwill205 This is correct, but how did you go from
to
?
So, 
