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

• gajohnson
gajohnson

## Homework Statement

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

http://grab.by/mGxY

## 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!

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?

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

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

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 $I(x-x_n)≤0$?

Homework Helper
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 $I(x-x_n)≤0$?

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