Radius Interval
1. The problem is to find the radius and interval of convergence of the series $$\sum_{n=0}^\infty (x+5)^n$$ and determine for which values of $x$ the series converges.
2. This is a geometric series with common ratio $r = x+5$.
3. A geometric series converges if and only if $$|r| < 1$$.
4. Applying this to our series, we have $$|x+5| < 1$$.
5. Solve the inequality:
$$-1 < x+5 < 1$$
6. Subtract 5 from all parts:
$$-6 < x < -4$$
7. The radius of convergence $R$ is the distance from the center $-5$ to either endpoint, so:
$$R = 1$$
8. The interval of convergence is $$(-6, -4)$$.
9. Check endpoints:
- At $x = -6$, the series becomes $$\sum_{n=0}^\infty (-1)^n$$ which does not converge.
- At $x = -4$, the series becomes $$\sum_{n=0}^\infty 1^n$$ which diverges.
10. Therefore, the series converges for $$x$$ in the open interval $$(-6, -4)$$ only.
Final answer: Radius of convergence is $1$, interval of convergence is $$(-6, -4)$$, and the series converges for $$x$$ such that $$-6 < x < -4$$.