\sqrt[3]{x + 1} - \sqrt[3]{x}\begin{array}{l}
\mathbf{if}\;x \le -56162.19239214984554564580321311950683594 \lor \neg \left(x \le 70939.05875514661602210253477096557617188\right):\\
\;\;\;\;\left(\sqrt[3]{x} - \sqrt[3]{-1} \cdot \sqrt[3]{-x}\right) + \frac{\sqrt[3]{x}}{x} \cdot \left(0.3333333333333333148296162562473909929395 - \frac{0.1111111111111111049432054187491303309798}{x}\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt[3]{\sqrt[3]{x + 1} \cdot \sqrt[3]{x + 1}} \cdot \sqrt[3]{\sqrt[3]{x + 1}} - \sqrt[3]{x}\\
\end{array}double f(double x) {
double r45838 = x;
double r45839 = 1.0;
double r45840 = r45838 + r45839;
double r45841 = cbrt(r45840);
double r45842 = cbrt(r45838);
double r45843 = r45841 - r45842;
return r45843;
}
double f(double x) {
double r45844 = x;
double r45845 = -56162.192392149846;
bool r45846 = r45844 <= r45845;
double r45847 = 70939.05875514662;
bool r45848 = r45844 <= r45847;
double r45849 = !r45848;
bool r45850 = r45846 || r45849;
double r45851 = cbrt(r45844);
double r45852 = -1.0;
double r45853 = cbrt(r45852);
double r45854 = -r45844;
double r45855 = cbrt(r45854);
double r45856 = r45853 * r45855;
double r45857 = r45851 - r45856;
double r45858 = r45851 / r45844;
double r45859 = 0.3333333333333333;
double r45860 = 0.1111111111111111;
double r45861 = r45860 / r45844;
double r45862 = r45859 - r45861;
double r45863 = r45858 * r45862;
double r45864 = r45857 + r45863;
double r45865 = 1.0;
double r45866 = r45844 + r45865;
double r45867 = cbrt(r45866);
double r45868 = r45867 * r45867;
double r45869 = cbrt(r45868);
double r45870 = cbrt(r45867);
double r45871 = r45869 * r45870;
double r45872 = r45871 - r45851;
double r45873 = r45850 ? r45864 : r45872;
return r45873;
}



Bits error versus x
Results
if x < -56162.192392149846 or 70939.05875514662 < x Initial program 60.4
rmApplied add-cube-cbrt60.5
Applied cbrt-prod60.6
Taylor expanded around -inf 64.0
Simplified0.7
if -56162.192392149846 < x < 70939.05875514662Initial program 0.2
rmApplied add-cube-cbrt0.2
Applied cbrt-prod0.2
Final simplification0.4
herbie shell --seed 2019304
(FPCore (x)
:name "2cbrt (problem 3.3.4)"
:precision binary64
(- (cbrt (+ x 1)) (cbrt x)))