Find all values of x for which the series converges. (Enter your answer using interval notation.)

For these values of x, write the sum of the series as a function of x.

Revelant knowledge

A series is considered to be convergent (or is convergent) when the order of its sums is close to a specific limit. That means that when adding one after the next in the order specified through the indexes one will get partial sums that get closer and closer to a certain number.