(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Let S be the subset of the integers {0, 1, 2, 3, 4, 5, 6}, and let f be the function from S to S defined by f(x) = (4x+3) mod 7. Find a formula for f<superscript>-1 (the inverse of f, I don't know how to type that).

2. Relevant equations

I know that the mod function is defined by floor function (a - n floor(n\a). But I'm still unable to create an inverse function with one inverse function for all values. I made a piecewise function that works for those values, but I feel like there should be a better method. Does anybody know an inverse rule for either floor or modulus?

3. The attempt at a solution

f(x) = {2x+1, 0 <= x <= 2}

{2x-6, 3 <= x <= 6}

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Inverse of Mod Function

**Physics Forums | Science Articles, Homework Help, Discussion**