code: function(poly) {
              var l = Math.max(this.coeffs.length, poly.coeffs.length);
              for(var i=0; i<l; i++) {
                  var a = (this.coeffs[i] || new Frac(0)),
                      b = (poly.coeffs[i] || new Frac(0));
                  this.coeffs[i] = a.add(b);
              }
              return this;
          }
docs: Adds together 2 polynomials
  @param {Polynomial} poly