We have found that the given power series converges for ∣x∣<5 and also for the endpolnt x=5. Finally, we must test the second endpoint of the interval, x=−5. ∑ n=1
[infinity]
​
n 4
5 n
(−5) n
​
=∑ n=1
[infinity]
​
n 4
(−1) n
​
By the Alternating Serles Test, this series To conclude, find the interval, I, of convergence of the series. (Enter your answer using interval notation.) I=