J ' v ( z ) = z v 1 2 v k = 0 z 2 4 k ( v + 2k ) k ! Γ ( 1 + k + v ) Y ' v ( x ) = Γ ( v ) cos ( v π ) π × z v 1 2 v × k = 0 z 2 4 k ( v + 2k ) ( v + 1 ) k k ! Γ ( v ) π × 2 v z v + 1 × k = 0 z 2 4 k ( 2k v ) ( 1 v ) k k !