code: public static ComplexNumber Exp(ComplexNumber z1) {
          ComplexNumber x, y;
          x = new ComplexNumber(Math.exp(z1.real), 0.0);
          y = new ComplexNumber(Math.cos(z1.imaginary), Math.sin(z1.imaginary));
  
          return Multiply(x, y);
      }
docs: Calculates exponent (e raised to the specified power) of a complex number.
  
  @param z1 A Complex Number instance.
  @return Returns new ComplexNumber instance containing the exponent of the specified complex number.