Answer
The interval of convergence for the series is: $[-1,1]$ and the radius of convergence is $R=1$.
Work Step by Step
Ratio Test: Let us consider a series $\Sigma a_k$ whose limit $l$ can be obtained as: $ l=\lim\limits_{k \to \infty} |\dfrac{a_{k+1}}{a_k}|$
1. For $l \lt 1$, the series is absolutely convergent.
2. For $l \gt 1$, the series is divergent.
3. For $l = 1$, the series is inconclusive.
Therefore, $l=\lim\limits_{k \to \infty} |\dfrac{a_{k+1}}{a_k}|\\=\lim\limits_{k \to \infty} \dfrac{x^{k+1}}{ (k+1)(k+2)} \times \dfrac{ k(k+1)}{x^{k+1}} \\=\lim\limits_{k \to \infty} \dfrac{ k }{(k+2)}|x|\\= |x|$
So, we can conclude that the given series converges absolutely if $l=|x| \lt 1$, and the test is inconclusive if $|x| =1$ for $x=1$ or $x=-1$. It diverges if $l=|x| \gt 1$ .
Therefore, the interval of convergence for the series is: $[-1,1]$ and the radius of convergence is $R=1$.