Question

Help, how do you solve this series?

Answer 1

\[\sum_{n=1}^{\infty}(-1)^{n+1} (3n \div 1 + 3n ^{2})\]

Answer 2

what do you mean by solve?

Answer 3

if its convergent or divergent

Answer 4

use the alternating series test

Answer 5

I am confused by your series. Why is there a division by 1? Do you intend simply the following?
\[\sum_{n=1}^{\infty}(-1)^{n+1} \frac{3n}{1+3n^2}\]

Answer 6

i think that is what he means

Answer 7

\[\sum_{}^{}(-1)^{n+1}b_n\]

see if \[b_n->0 \text{ as } n-> \infty \text{ and see if } b_n>b_{n+1}\]

Answer 8

if both of those are met then it is convergent