4. (a) Verify that f(z) = e/ has exactly one singularity, namely z = 0. (b) For a real number r > 0, let D, be the punctured disk Dr = { z C: 0 < |z| 0, the function (z) = e/ maps D, onto C - {0}. (Hint: Where does exp(z) = e map the set {ZEC : |Z| > } } ?) (c) Use part (b) to show that there is no w EC such that the function 8w (2) = Sel/z W ifz #0 if z = 0