\frac{\frac{\beta - \alpha}{\left(\alpha + \beta\right) + 2} + 1}{2}\begin{array}{l}
\mathbf{if}\;\alpha \le 1188863810682620.75:\\
\;\;\;\;\frac{\sqrt[3]{{\left(\frac{\beta}{\left(\alpha + \beta\right) + 2}\right)}^{3}} - \left(\frac{\alpha}{\left(\alpha + \beta\right) + 2} - 1\right)}{2}\\
\mathbf{else}:\\
\;\;\;\;\frac{\frac{\beta}{\left(\alpha + \beta\right) + 2} - \left(\frac{\frac{4}{\alpha}}{\alpha} - \left(\frac{2}{\alpha} - \frac{-8}{{\alpha}^{3}}\right)\right)}{2}\\
\end{array}double f(double alpha, double beta) {
double r113560 = beta;
double r113561 = alpha;
double r113562 = r113560 - r113561;
double r113563 = r113561 + r113560;
double r113564 = 2.0;
double r113565 = r113563 + r113564;
double r113566 = r113562 / r113565;
double r113567 = 1.0;
double r113568 = r113566 + r113567;
double r113569 = r113568 / r113564;
return r113569;
}
double f(double alpha, double beta) {
double r113570 = alpha;
double r113571 = 1188863810682620.8;
bool r113572 = r113570 <= r113571;
double r113573 = beta;
double r113574 = r113570 + r113573;
double r113575 = 2.0;
double r113576 = r113574 + r113575;
double r113577 = r113573 / r113576;
double r113578 = 3.0;
double r113579 = pow(r113577, r113578);
double r113580 = cbrt(r113579);
double r113581 = r113570 / r113576;
double r113582 = 1.0;
double r113583 = r113581 - r113582;
double r113584 = r113580 - r113583;
double r113585 = r113584 / r113575;
double r113586 = 4.0;
double r113587 = r113586 / r113570;
double r113588 = r113587 / r113570;
double r113589 = r113575 / r113570;
double r113590 = 8.0;
double r113591 = -r113590;
double r113592 = pow(r113570, r113578);
double r113593 = r113591 / r113592;
double r113594 = r113589 - r113593;
double r113595 = r113588 - r113594;
double r113596 = r113577 - r113595;
double r113597 = r113596 / r113575;
double r113598 = r113572 ? r113585 : r113597;
return r113598;
}



Bits error versus alpha



Bits error versus beta
Results
if alpha < 1188863810682620.8Initial program 0.3
rmApplied div-sub0.3
Applied associate-+l-0.3
rmApplied add-cbrt-cube11.2
Applied add-cbrt-cube13.7
Applied cbrt-undiv13.7
Simplified0.3
if 1188863810682620.8 < alpha Initial program 50.2
rmApplied div-sub50.2
Applied associate-+l-48.7
Taylor expanded around inf 18.3
Simplified18.3
Final simplification6.0
herbie shell --seed 2020025
(FPCore (alpha beta)
:name "Octave 3.8, jcobi/1"
:precision binary64
:pre (and (> alpha -1) (> beta -1))
(/ (+ (/ (- beta alpha) (+ (+ alpha beta) 2)) 1) 2))