Is it possible to construct a real function that is continuous at only one point?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Consider the function:
f ( x ) = { x if x ∈ Q 0 if x ∈ Q
It is discontinuous at all points except for x = 0 .