a) find a Laurent series for z/(z^2 -4) in the region |z|>2. I got this part, this is sum (2^(n-2) ((-1)^(n-1)+1) z^(-n) , n from 1 to infinitive

b) Use the series from a) to find integral along gamma of z/(z^2 -4) dz where gamma(t) = 4e^(it) 0< = t < = 2 pi. Be sure to explain why you can interchange summation and integration when evaluating . I need help on this part (b) .