I have a question about the february 2004 midterm practise exam.
For #2b, the series is a telescoping series so we need to find the nth partial sum.
Why does Sn stop at n=n-1? Why doesn't Sn stop at n=n+2?
It does not matter, since lim(sn) is the same as lim(sn+2) as n goes to infinity. In other words, if you use sn+2 and you will get the same answer.