23 P 111 LLL Find all possible Laurent expansions centered at 0 of the following functions a b c 2 1 2 4 b In the region 1 we have 2 1 2 1 1 1 2 1 1 2 2 2 1 In the region 2 1 we have 1 k 0 K 2 2 1 1 k zk 1 2 1 2 1 2 1 1 2 1 2 n 1 2 z 1 1 k 1 n 1 2 n 0 2 7 n 1 1 k k 0 1 1 2n 1 2 1 zn n 1