# Thread: series conv or div

1. ## series conv or div

series conv or div for sum (2 +(-1)^n)/(nsquarerootn)

2. Note that: $0 < 2 + (-1)^n \leq 3$

So use the comparison test noting that: $\frac{2 + (-1)^n}{n \cdot n^{\frac{1}{2}}} \ \leq \ \frac{3}{n^{\frac{3}{2}}}$

3. why isnt the series between 1 and 3 instead of 0 and 3