Find the radius of convergence, R, of the series. n = 2 x7 +9 9n! Find the interval, I, of convergence of the series. (Enter your answer using interval notation.) Step 1 We will use the Ratio Test to determine the radius of convergence. We have the following. lim an+1 n→ ∞ lim n → ∞o an x + 10 9(n + 1)! +7 +9 9n! = lim x + 10 9 n! no 9(n+1)! n! x7 + 9 Step 2 Simplifying, we get lim n → ∞ n+1 Step 3 Therefore, we now have the following. lim n→ ∞ n+1 1 = |x| lim an noon + 1 = |×| · . X n+1