In: Advanced Math
For an integer k, define f(k) = gcd(11k + 1, 7k + 3).
(a) Compute R = {f(k): k ∈ Z}.
(b) For each n ∈ R, find a set Dn such that, for every
integer k, f(k) = n if and only if k ∈ Dn.
Is there any solution without using the 'mod' for b?