What Are the Discontinuities of the Function g on the Interval [0,1]?

  • Thread starter Thread starter foxjwill
  • Start date Start date
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
1 reply · 2K views
foxjwill
Messages
350
Reaction score
0

Homework Statement


Find (and prove as such) all discontinuities of the function [tex]g:[0,1]\to\mathbb{R}[/tex] given by
[tex]g(x)=\sum_{n=1}^\infty \frac{1}{2^{2n-1}}\left\lfloor \frac{2^nx+1}{2} \right\rfloor[/tex]​
where [tex]\lfloor\cdot\rfloor[/tex] is the greatest integer function.

Homework Equations





The Attempt at a Solution


I'm pretty sure that the discontinuities all occur at [tex]x=(2k+1)2^{-m}[/tex] for positive integer [tex]k,m[/tex] since this is where the expression inside the greatest integer function is an integer. The thing is, I have no how to go about proving that these points are discontinuous. Can anyone steer me in the right direction?
 
Physics news on Phys.org
When x hits that point, note that every term in the sum is
1) positive
2) larger when you cross over the point

And you get that as you approach (2k+1)2-m from the right, each term is strictly larger than when you approach from the left