I wanted to create a forum where students can help other students who are having trouble with the WebWork problems. I don’t know why this hasn’t been done before, but it’s never too late to ask for help.
I also find it particularly annoying to keep going back to the OpenLab Homework Assignment #4 post to get the link to log into WebWork. Hopefully, most of you are smarter and just made the link a bookmark or a pinned tab in your browser but, if you haven’t, clicking any of the webwork links or webwork icons above will take you there. You can also right click any of them and select “Copy Link Location”, to get the url and save it somewhere.
I’d say, as far as asking for help goes, try to use 
And, this kind of goes without saying but, Mr Reitz can obviously read this so it wouldn’t behoove you to flat out ask others for answers on here. And, if that happens, this post will likely get deleted. So with that in mind, use it as you will.
Hope this helps.
So, I’ll start things off…
With Webwork assignment 4-11.1, there are a few problems towards the end that require a convergent sum but are not geometric sequences like:
Problem 19
The sum of all terms for:
when n = [1,infinity]
Problem 20
The sum of all terms for:
when n = [1,infinity]
For problem 19, the terms’ denominators increase by a factor of 11, but the terms’ numerators have no common factors. And for problem 20, the terms’ numerators don’t change (it’s always 7), but the terms’ denominators have no common factors.
How do you guys go about solving these?