code: function() {
  
        /**
         * exp(a + i*b) - 1
         = exp(a) * (cos(b) + j*sin(b)) - 1
         = expm1(a)*cos(b) + cosm1(b) + j*exp(a)*sin(b)
         */
  
        var a = this['re'];
        var b = this['im'];
  
        return new Complex(
                Math.expm1(a) * Math.cos(b) + cosm1(b),
                Math.exp(a) * Math.sin(b));
      }
docs: Calculate the complex exponent and subtracts one.
  
  This may be more accurate than `Complex(x).exp().sub(1)` if
  `x` is small.
  
  @returns {Complex}