1. ## comparison test.

here is the problem: ImageShack - Image Hosting :: 77517802tm8.jpg

we haven't learned the alternating series test.

not sure what to compare it to. the series converges, however i thought it behaved like a diverging p series.

need help.

2. Originally Posted by rcmango
here is the problem: ImageShack - Image Hosting :: 77517802tm8.jpg

we haven't learned the alternating series test.

not sure what to compare it to. the series converges, however i thought it behaved like a diverging p series.

need help.
Since $2 +(-1)^n \le 3$ then $\sum_{i=1}^{\infty} \frac{2 + (-1)^n}{n\sqrt{n}} \le \sum_{i=1}^{\infty} \frac{3}{n\sqrt{n}}$ so by the direct comparison test your series converges.

3. hey thanks.