Assuming you meant "where <em />x is any integer":
is defined as 
, so it would be defined for every value of 
except for those where 
, which is true when 
and 
, where 
is some integer. These values of where is undefined are both <em>irrational</em><em>; </em>they cannot be expressed as a ratio between two integers, and so limiting the domain to integers makes sure that we'll skip over those points every time as is increasing.
So, the domain of
, when limiting that domain to the integers, is the set of all integers, 
.
So, the domain of