What is the reciprocal function?

The reciprocal function is:
##f(x)=1/x##
It’s graph is as following:
This is an example of asymptote.
Since ##x## can take all values except ##0## for ##f(x)## to be defined
: ##R-{0}## i.e. all real numbers except 0.
: ##R-{0}## i.e. all real numbers except 0.