# Sequences and Series of Functions Question (Rudin Chapter 7)

1. May 19, 2013

### gajohnson

1. The problem statement, all variables and given/known data

The problem is Exercise 8 from Chapter 7 of Rudin. It can be seen here:

http://grab.by/mGxY

2. Relevant equations

3. The attempt at a solution

It seems quite obvious to see that because $\sum\left|c_n\right|$ converges, $f(x)$ will converge uniformly.

However, I am having a difficult time understanding why $f(x)$ will be continuous at all $x\neq{x_n}$

Any help with understanding this second part of the proof would be greatly appreciated. Thanks!

2. May 19, 2013

### gajohnson

Is this as simple as stating that there is a jump discontinuity at $x=x_n$, because the left-hand limit = 0, and the right-hand limit = 1?

3. May 19, 2013

### verty

Which c_n's does I(x - x_n) choose to exclude from the sum?

4. May 19, 2013

### gajohnson

I'm not quite sure I understand your question. Do you mean for me to say that $c_n$ is excluded from the sum when $I(x-x_n)≤0$?

5. May 19, 2013

### verty

I can't really say more without being too helpful.