<Moderator's note: moved from a technical forum, so homework template missing> Hi. I have solved the others but I am really struggling on 22c. I need it to converge for |z|>2. This is the part I am really struggling with. I am trying to get both fractions into a geometric series with 1/(1-(1/(z/2)) so that it converges for 1/(z/2) <1; which becomes, (z>2). I however cannot manipulate either series into this form that I am looking for. I have tried many times. I have also tried combining both fractions into one fraction over z^2-1, but am not getting anywhere. Any pointers, or tips so that I can get it to converge for |z|>2 by manipulating the fractions (just simply cannot get in right form). Thank you.