Power Series (Not a test question)

Question

Which of the following intervals is impossible for the convergence of the power series  ?

	0 < x < 6
	1 ≤ x ≤ 9
	2 ≤ x ≤ 8
	3 ≤ x ≤ 7

I got the interval of convergence is 4<x<6, but how do I find when it is impossible to converge? Please help me and thank you in advance

Answer 1

The interval of convergence must be centered on 5.

The one which won't work is 0<x<6.