Finding the Interval for Power Series Summation of x^(n)/[2^(n)*n^(4)]

[frasifrasi]

For summation from 1 to infinity of x^(n)/[2^(n)*n^(4)]
- I get the radius is 2 by ration test, but how do I get the interval, just by pluggin in?

 

[frasifrasi]

anyone? : )

 

[rocomath]

well it's just -1<x<1

so your R is 2, but before you had x/2

-1<x/2<1

-2<x<2 (equal to)