So far I have this:Find the radius of convergence of the power series for the following choices of

for some constant

but

Therefore:

This will only converge if . Hence the radius of convergence of is 1 (ie. ).

So I have an upper bound, but I can't find a lower bound. Since x can be negative (i'm assuming from the question that ) I can't just make the original power series greater than 1!

Any help would be great!