How to solve pls once show step

https://math.stackexchange.com/questions/344483/radius-of-convergence-of-power-series-sum-c-n-x2n-and-sum-c-n-xn2#:~:text=If%200%3Ca%3C1%20then,n2%20is%201%2Fa.

make the notes from this article . it will be helpful for u in further questions

everthing is given . all u need to put your sequence . radius of convergence will be 1

read this article https://math.stackexchange.com/questions/344483/radius-of-convergence-of-power-series-sum-c-n-x2n-and-sum-c-n-xn2