For which values of x does the power series converge or diverge?
Solution 1:
The power series must be convergent when $x$ satisfies that $-R <x+2< R$, and be divergent when $x <-R$ and $x>R$ and be unkown when $x+2=-R$ or $x+2=R$, where $2\le R \le 3$.
So (a) is convergent; $b$ is divergent; $c$ and $d$ are unknown.