Say I have a set $E$ with an arbitrary number of elements which are of the form $f$ i.e. $E=\{f(x):x \in\Bbb N\}$ and a set $G$ with an arbitrary number of elements which are of the form $h$ i.e. $G=\{h(a):a\in\Bbb Z\}$.
What would be the general strategy of showing that these two sets are disjoint. I have a basic idea on how to start: Assume for the sake of contradiction that the two sets do have some common elements. How would I then show that this leads to a contradiction allowing me to conclude that $E$ intersection $G$ is the null set. Once again, I just want a general approach to solving this problem. Thanks.