i s analytic in the mtirt cmniplcx plaiic, except tor the points i = U U’ithiii tlic region of convcrgcrrcc of L’(s) r“(‘Sj = I(s) : Et.{.) ;’ -0 (5.X) 111cotitrast t h F ( s ) , i t i s possibl(>t o dioose it closed path of inkgraliiin with 5cld of icgnlaiity that crrcloscs thr polc s = - 1 (compare Fig 5.4) A