code: function() {
  
        // sin(c) = (e^b - e^(-b)) / (2i)
  
        var a = this['re'];
        var b = this['im'];
  
        return new Complex(
                Math.sin(a) * cosh(b),
                Math.cos(a) * sinh(b));
      }
docs: Calculate the sine of the complex number
  
  @returns {Complex}