For a set S:

S = (0,1) U (3,4) U (5, +infinity)

you can press the button to be given a point x0 of S. Your job is to find a value of r such that (x0-r, x0+r) belongs entirely to S.

Given a point x0 in S...
Find an r such that (x0-r x0+r) is a subset of S.

Analysis WebNotes by John Lindsay Orr.
Comments to the author: jorr@math.unl.edu

All contents copyright (C) 1996 John L. Orr
University of Nebraska--Lincoln
All rights reserved

Last modified: May 1996