\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\pi \cdot \frac{angle}{180}\right)\right) \cdot \cos \left(\pi \cdot \frac{angle}{180}\right)
\begin{array}{l}
t_0 := 0.005555555555555556 \cdot \left(angle \cdot \pi\right)\\
t_1 := \sqrt[3]{\cos t_0}\\
\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin t_0\right) \cdot \left(t_1 \cdot \left(\sqrt[3]{\cos \left(\pi \cdot \frac{angle}{180}\right)} \cdot t_1\right)\right)
\end{array}
(FPCore (a b angle) :precision binary64 (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin (* PI (/ angle 180.0)))) (cos (* PI (/ angle 180.0)))))
(FPCore (a b angle)
:precision binary64
(let* ((t_0 (* 0.005555555555555556 (* angle PI))) (t_1 (cbrt (cos t_0))))
(*
(* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin t_0))
(* t_1 (* (cbrt (cos (* PI (/ angle 180.0)))) t_1)))))double code(double a, double b, double angle) {
return ((2.0 * (pow(b, 2.0) - pow(a, 2.0))) * sin(((double) M_PI) * (angle / 180.0))) * cos(((double) M_PI) * (angle / 180.0));
}
double code(double a, double b, double angle) {
double t_0 = 0.005555555555555556 * (angle * ((double) M_PI));
double t_1 = cbrt(cos(t_0));
return ((2.0 * (pow(b, 2.0) - pow(a, 2.0))) * sin(t_0)) * (t_1 * (cbrt(cos(((double) M_PI) * (angle / 180.0))) * t_1));
}



Bits error versus a



Bits error versus b



Bits error versus angle
Results
Initial program 31.4
Applied add-cube-cbrt_binary6431.4
Taylor expanded in angle around inf 31.3
Taylor expanded in angle around inf 31.4
Taylor expanded in angle around inf 31.3
Final simplification31.3
herbie shell --seed 2022081
(FPCore (a b angle)
:name "ab-angle->ABCF B"
:precision binary64
(* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin (* PI (/ angle 180.0)))) (cos (* PI (/ angle 180.0)))))