Find the radius of convergence, R, of the series. Then find the interval, I, of convergence of the series. Σ n = 1 хл nAgn Step 1 We are given the following power series and must determine the radius of convergence, R. Σ хл n4gn n = 1 Recall that a power series centered at a is of the form ✗C_)(x - a)". The radius of convergence is the positive value R such that the power series converges if |x - a| < R and diverges if |x - al > R. The given power series is centered at n = 0 Let an = To begin, find and simplify the limit. xn be the terms of the given power series. By the Ratio Test, we know the convergence of the power series can be tested with the limit of n4gn an + 1 a, an lim n→ ∞ an+1 a n +7 +1 = lim n→ ∞ (n + 1)4 9n+1 x7 nAgn = lim n→ ∞ (n + 1)4 = ☑ 9 lim n→ ∞ ☑ 9 n + 1 9 Xa 4