
(FPCore (x) :precision binary64 (- (cbrt (+ x 1.0)) (cbrt x)))
double code(double x) {
return cbrt((x + 1.0)) - cbrt(x);
}
public static double code(double x) {
return Math.cbrt((x + 1.0)) - Math.cbrt(x);
}
function code(x) return Float64(cbrt(Float64(x + 1.0)) - cbrt(x)) end
code[x_] := N[(N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision] - N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{x + 1} - \sqrt[3]{x}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 11 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (- (cbrt (+ x 1.0)) (cbrt x)))
double code(double x) {
return cbrt((x + 1.0)) - cbrt(x);
}
public static double code(double x) {
return Math.cbrt((x + 1.0)) - Math.cbrt(x);
}
function code(x) return Float64(cbrt(Float64(x + 1.0)) - cbrt(x)) end
code[x_] := N[(N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision] - N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{x + 1} - \sqrt[3]{x}
\end{array}
(FPCore (x) :precision binary64 (let* ((t_0 (cbrt (sqrt (+ 1.0 x)))) (t_1 (cbrt (+ 1.0 x)))) (/ 1.0 (fma (cbrt x) (+ (cbrt x) (* t_0 t_0)) (* t_1 t_1)))))
double code(double x) {
double t_0 = cbrt(sqrt((1.0 + x)));
double t_1 = cbrt((1.0 + x));
return 1.0 / fma(cbrt(x), (cbrt(x) + (t_0 * t_0)), (t_1 * t_1));
}
function code(x) t_0 = cbrt(sqrt(Float64(1.0 + x))) t_1 = cbrt(Float64(1.0 + x)) return Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + Float64(t_0 * t_0)), Float64(t_1 * t_1))) end
code[x_] := Block[{t$95$0 = N[Power[N[Sqrt[N[(1.0 + x), $MachinePrecision]], $MachinePrecision], 1/3], $MachinePrecision]}, Block[{t$95$1 = N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]}, N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[(t$95$0 * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(t$95$1 * t$95$1), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{\sqrt{1 + x}}\\
t_1 := \sqrt[3]{1 + x}\\
\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + t\_0 \cdot t\_0, t\_1 \cdot t\_1\right)}
\end{array}
\end{array}
Initial program 7.3%
flip3--7.7%
div-inv7.7%
rem-cube-cbrt7.2%
rem-cube-cbrt10.1%
+-commutative10.1%
distribute-rgt-out10.1%
+-commutative10.1%
fma-define10.1%
add-exp-log10.1%
Applied egg-rr10.1%
associate-*r/10.1%
*-rgt-identity10.1%
+-commutative10.1%
associate--l+93.5%
+-inverses93.5%
metadata-eval93.5%
+-commutative93.5%
exp-prod92.2%
Simplified92.2%
pow-exp93.5%
*-commutative93.5%
log1p-undefine93.5%
+-commutative93.5%
exp-to-pow93.0%
metadata-eval93.0%
pow-prod-up93.0%
pow1/394.4%
pow1/398.6%
Applied egg-rr98.6%
+-commutative98.6%
expm1-log1p-u95.6%
Applied egg-rr95.6%
expm1-log1p-u98.6%
pow1/394.4%
add-sqr-sqrt94.4%
unpow-prod-down94.4%
Applied egg-rr94.4%
unpow1/395.9%
+-commutative95.9%
unpow1/398.6%
+-commutative98.6%
Simplified98.6%
Final simplification98.6%
(FPCore (x)
:precision binary64
(let* ((t_0 (cbrt (+ 1.0 x))))
(if (<= (- t_0 (cbrt x)) 0.0)
(/ 1.0 (fma (cbrt x) (+ (cbrt x) t_0) 1.0))
(+
(pow (pow (+ 1.0 x) 0.16666666666666666) 2.0)
(- 0.0 (pow x 0.3333333333333333))))))
double code(double x) {
double t_0 = cbrt((1.0 + x));
double tmp;
if ((t_0 - cbrt(x)) <= 0.0) {
tmp = 1.0 / fma(cbrt(x), (cbrt(x) + t_0), 1.0);
} else {
tmp = pow(pow((1.0 + x), 0.16666666666666666), 2.0) + (0.0 - pow(x, 0.3333333333333333));
}
return tmp;
}
function code(x) t_0 = cbrt(Float64(1.0 + x)) tmp = 0.0 if (Float64(t_0 - cbrt(x)) <= 0.0) tmp = Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + t_0), 1.0)); else tmp = Float64(((Float64(1.0 + x) ^ 0.16666666666666666) ^ 2.0) + Float64(0.0 - (x ^ 0.3333333333333333))); end return tmp end
code[x_] := Block[{t$95$0 = N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]}, If[LessEqual[N[(t$95$0 - N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision], 0.0], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + t$95$0), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision], N[(N[Power[N[Power[N[(1.0 + x), $MachinePrecision], 0.16666666666666666], $MachinePrecision], 2.0], $MachinePrecision] + N[(0.0 - N[Power[x, 0.3333333333333333], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{1 + x}\\
\mathbf{if}\;t\_0 - \sqrt[3]{x} \leq 0:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + t\_0, 1\right)}\\
\mathbf{else}:\\
\;\;\;\;{\left({\left(1 + x\right)}^{0.16666666666666666}\right)}^{2} + \left(0 - {x}^{0.3333333333333333}\right)\\
\end{array}
\end{array}
if (-.f64 (cbrt.f64 (+.f64 x 1)) (cbrt.f64 x)) < 0.0Initial program 4.2%
flip3--4.2%
div-inv4.2%
rem-cube-cbrt3.3%
rem-cube-cbrt4.2%
+-commutative4.2%
distribute-rgt-out4.2%
+-commutative4.2%
fma-define4.2%
add-exp-log4.2%
Applied egg-rr4.2%
associate-*r/4.2%
*-rgt-identity4.2%
+-commutative4.2%
associate--l+93.2%
+-inverses93.2%
metadata-eval93.2%
+-commutative93.2%
exp-prod91.9%
Simplified91.9%
Taylor expanded in x around 0 20.0%
if 0.0 < (-.f64 (cbrt.f64 (+.f64 x 1)) (cbrt.f64 x)) Initial program 53.4%
pow1/349.4%
Applied egg-rr49.4%
add-sqr-sqrt49.6%
pow249.6%
pow1/354.1%
sqrt-pow154.3%
metadata-eval54.3%
Applied egg-rr54.3%
Final simplification22.1%
(FPCore (x)
:precision binary64
(let* ((t_0 (+ (cbrt x) (cbrt (+ 1.0 x)))))
(if (<= x 1.35e+154)
(/ 1.0 (fma (cbrt x) t_0 (cbrt (pow (+ 1.0 x) 2.0))))
(/ 1.0 (fma (cbrt x) t_0 (exp (* (log1p x) 0.6666666666666666)))))))
double code(double x) {
double t_0 = cbrt(x) + cbrt((1.0 + x));
double tmp;
if (x <= 1.35e+154) {
tmp = 1.0 / fma(cbrt(x), t_0, cbrt(pow((1.0 + x), 2.0)));
} else {
tmp = 1.0 / fma(cbrt(x), t_0, exp((log1p(x) * 0.6666666666666666)));
}
return tmp;
}
function code(x) t_0 = Float64(cbrt(x) + cbrt(Float64(1.0 + x))) tmp = 0.0 if (x <= 1.35e+154) tmp = Float64(1.0 / fma(cbrt(x), t_0, cbrt((Float64(1.0 + x) ^ 2.0)))); else tmp = Float64(1.0 / fma(cbrt(x), t_0, exp(Float64(log1p(x) * 0.6666666666666666)))); end return tmp end
code[x_] := Block[{t$95$0 = N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[x, 1.35e+154], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * t$95$0 + N[Power[N[Power[N[(1.0 + x), $MachinePrecision], 2.0], $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * t$95$0 + N[Exp[N[(N[Log[1 + x], $MachinePrecision] * 0.6666666666666666), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{x} + \sqrt[3]{1 + x}\\
\mathbf{if}\;x \leq 1.35 \cdot 10^{+154}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, t\_0, \sqrt[3]{{\left(1 + x\right)}^{2}}\right)}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, t\_0, e^{\mathsf{log1p}\left(x\right) \cdot 0.6666666666666666}\right)}\\
\end{array}
\end{array}
if x < 1.35000000000000003e154Initial program 10.1%
flip3--10.9%
div-inv10.9%
rem-cube-cbrt11.7%
rem-cube-cbrt16.0%
+-commutative16.0%
distribute-rgt-out16.1%
+-commutative16.1%
fma-define16.0%
add-exp-log16.0%
Applied egg-rr16.0%
associate-*r/16.0%
*-rgt-identity16.0%
+-commutative16.0%
associate--l+95.2%
+-inverses95.2%
metadata-eval95.2%
+-commutative95.2%
exp-prod93.7%
Simplified93.7%
pow-exp95.2%
*-commutative95.2%
log1p-undefine95.2%
+-commutative95.2%
exp-to-pow94.5%
metadata-eval94.5%
pow-prod-up94.5%
pow1/395.9%
pow1/398.5%
cbrt-unprod98.8%
pow298.8%
Applied egg-rr98.8%
if 1.35000000000000003e154 < x Initial program 4.7%
flip3--4.7%
div-inv4.7%
rem-cube-cbrt3.2%
rem-cube-cbrt4.7%
+-commutative4.7%
distribute-rgt-out4.7%
+-commutative4.7%
fma-define4.7%
add-exp-log4.7%
Applied egg-rr4.7%
associate-*r/4.7%
*-rgt-identity4.7%
+-commutative4.7%
associate--l+92.0%
+-inverses92.0%
metadata-eval92.0%
+-commutative92.0%
exp-prod90.9%
Simplified90.9%
pow-exp92.0%
*-commutative92.0%
Applied egg-rr92.0%
Final simplification95.2%
(FPCore (x) :precision binary64 (let* ((t_0 (cbrt (+ 1.0 x)))) (/ 1.0 (fma (cbrt x) (+ (cbrt x) t_0) (pow t_0 2.0)))))
double code(double x) {
double t_0 = cbrt((1.0 + x));
return 1.0 / fma(cbrt(x), (cbrt(x) + t_0), pow(t_0, 2.0));
}
function code(x) t_0 = cbrt(Float64(1.0 + x)) return Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + t_0), (t_0 ^ 2.0))) end
code[x_] := Block[{t$95$0 = N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]}, N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + t$95$0), $MachinePrecision] + N[Power[t$95$0, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{1 + x}\\
\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + t\_0, {t\_0}^{2}\right)}
\end{array}
\end{array}
Initial program 7.3%
flip3--7.7%
div-inv7.7%
rem-cube-cbrt7.2%
rem-cube-cbrt10.1%
+-commutative10.1%
distribute-rgt-out10.1%
+-commutative10.1%
fma-define10.1%
add-exp-log10.1%
Applied egg-rr10.1%
associate-*r/10.1%
*-rgt-identity10.1%
+-commutative10.1%
associate--l+93.5%
+-inverses93.5%
metadata-eval93.5%
+-commutative93.5%
exp-prod92.2%
Simplified92.2%
pow-exp93.5%
*-commutative93.5%
log1p-undefine93.5%
+-commutative93.5%
exp-to-pow93.0%
metadata-eval93.0%
pow-prod-up93.0%
pow1/394.4%
pow1/398.6%
Applied egg-rr98.6%
pow298.6%
Applied egg-rr98.6%
Final simplification98.6%
(FPCore (x) :precision binary64 (/ 1.0 (fma (cbrt x) (+ (cbrt x) (cbrt (+ 1.0 x))) (exp (* (log1p x) 0.6666666666666666)))))
double code(double x) {
return 1.0 / fma(cbrt(x), (cbrt(x) + cbrt((1.0 + x))), exp((log1p(x) * 0.6666666666666666)));
}
function code(x) return Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + cbrt(Float64(1.0 + x))), exp(Float64(log1p(x) * 0.6666666666666666)))) end
code[x_] := N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + N[Exp[N[(N[Log[1 + x], $MachinePrecision] * 0.6666666666666666), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + \sqrt[3]{1 + x}, e^{\mathsf{log1p}\left(x\right) \cdot 0.6666666666666666}\right)}
\end{array}
Initial program 7.3%
flip3--7.7%
div-inv7.7%
rem-cube-cbrt7.2%
rem-cube-cbrt10.1%
+-commutative10.1%
distribute-rgt-out10.1%
+-commutative10.1%
fma-define10.1%
add-exp-log10.1%
Applied egg-rr10.1%
associate-*r/10.1%
*-rgt-identity10.1%
+-commutative10.1%
associate--l+93.5%
+-inverses93.5%
metadata-eval93.5%
+-commutative93.5%
exp-prod92.2%
Simplified92.2%
pow-exp93.5%
*-commutative93.5%
Applied egg-rr93.5%
Final simplification93.5%
(FPCore (x) :precision binary64 (/ 1.0 (fma (cbrt x) (+ (cbrt x) (cbrt (+ 1.0 x))) (pow (+ 1.0 x) 0.6666666666666666))))
double code(double x) {
return 1.0 / fma(cbrt(x), (cbrt(x) + cbrt((1.0 + x))), pow((1.0 + x), 0.6666666666666666));
}
function code(x) return Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + cbrt(Float64(1.0 + x))), (Float64(1.0 + x) ^ 0.6666666666666666))) end
code[x_] := N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 0.6666666666666666], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + \sqrt[3]{1 + x}, {\left(1 + x\right)}^{0.6666666666666666}\right)}
\end{array}
Initial program 7.3%
flip3--7.7%
div-inv7.7%
rem-cube-cbrt7.2%
rem-cube-cbrt10.1%
+-commutative10.1%
distribute-rgt-out10.1%
+-commutative10.1%
fma-define10.1%
add-exp-log10.1%
Applied egg-rr10.1%
associate-*r/10.1%
*-rgt-identity10.1%
+-commutative10.1%
associate--l+93.5%
+-inverses93.5%
metadata-eval93.5%
+-commutative93.5%
exp-prod92.2%
Simplified92.2%
pow-exp93.5%
*-commutative93.5%
log1p-undefine93.5%
+-commutative93.5%
exp-to-pow93.0%
metadata-eval93.0%
pow-prod-up93.0%
pow1/394.4%
pow1/398.6%
Applied egg-rr98.6%
pow298.6%
pow1/393.0%
pow-pow93.0%
metadata-eval93.0%
Applied egg-rr93.0%
Final simplification93.0%
(FPCore (x) :precision binary64 (fma (pow x 0.16666666666666666) (- (pow x 0.16666666666666666)) (cbrt (+ 1.0 x))))
double code(double x) {
return fma(pow(x, 0.16666666666666666), -pow(x, 0.16666666666666666), cbrt((1.0 + x)));
}
function code(x) return fma((x ^ 0.16666666666666666), Float64(-(x ^ 0.16666666666666666)), cbrt(Float64(1.0 + x))) end
code[x_] := N[(N[Power[x, 0.16666666666666666], $MachinePrecision] * (-N[Power[x, 0.16666666666666666], $MachinePrecision]) + N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left({x}^{0.16666666666666666}, -{x}^{0.16666666666666666}, \sqrt[3]{1 + x}\right)
\end{array}
Initial program 7.3%
sub-neg7.3%
+-commutative7.3%
add-sqr-sqrt7.2%
distribute-rgt-neg-in7.2%
fma-define6.8%
pow1/38.2%
sqrt-pow18.2%
metadata-eval8.2%
pow1/38.1%
sqrt-pow18.1%
metadata-eval8.1%
Applied egg-rr8.1%
Final simplification8.1%
(FPCore (x) :precision binary64 (+ (cbrt (+ 1.0 x)) (- 0.0 (pow x 0.3333333333333333))))
double code(double x) {
return cbrt((1.0 + x)) + (0.0 - pow(x, 0.3333333333333333));
}
public static double code(double x) {
return Math.cbrt((1.0 + x)) + (0.0 - Math.pow(x, 0.3333333333333333));
}
function code(x) return Float64(cbrt(Float64(1.0 + x)) + Float64(0.0 - (x ^ 0.3333333333333333))) end
code[x_] := N[(N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision] + N[(0.0 - N[Power[x, 0.3333333333333333], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{1 + x} + \left(0 - {x}^{0.3333333333333333}\right)
\end{array}
Initial program 7.3%
pow1/38.1%
Applied egg-rr8.1%
Final simplification8.1%
(FPCore (x) :precision binary64 (- (cbrt (+ 1.0 x)) (cbrt x)))
double code(double x) {
return cbrt((1.0 + x)) - cbrt(x);
}
public static double code(double x) {
return Math.cbrt((1.0 + x)) - Math.cbrt(x);
}
function code(x) return Float64(cbrt(Float64(1.0 + x)) - cbrt(x)) end
code[x_] := N[(N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision] - N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{1 + x} - \sqrt[3]{x}
\end{array}
Initial program 7.3%
Final simplification7.3%
(FPCore (x) :precision binary64 0.0)
double code(double x) {
return 0.0;
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.0d0
end function
public static double code(double x) {
return 0.0;
}
def code(x): return 0.0
function code(x) return 0.0 end
function tmp = code(x) tmp = 0.0; end
code[x_] := 0.0
\begin{array}{l}
\\
0
\end{array}
Initial program 7.3%
Taylor expanded in x around inf 4.2%
Final simplification4.2%
(FPCore (x) :precision binary64 1.0)
double code(double x) {
return 1.0;
}
real(8) function code(x)
real(8), intent (in) :: x
code = 1.0d0
end function
public static double code(double x) {
return 1.0;
}
def code(x): return 1.0
function code(x) return 1.0 end
function tmp = code(x) tmp = 1.0; end
code[x_] := 1.0
\begin{array}{l}
\\
1
\end{array}
Initial program 7.3%
Taylor expanded in x around 0 6.2%
Final simplification6.2%
(FPCore (x) :precision binary64 (let* ((t_0 (cbrt (+ x 1.0)))) (/ 1.0 (+ (+ (* t_0 t_0) (* (cbrt x) t_0)) (* (cbrt x) (cbrt x))))))
double code(double x) {
double t_0 = cbrt((x + 1.0));
return 1.0 / (((t_0 * t_0) + (cbrt(x) * t_0)) + (cbrt(x) * cbrt(x)));
}
public static double code(double x) {
double t_0 = Math.cbrt((x + 1.0));
return 1.0 / (((t_0 * t_0) + (Math.cbrt(x) * t_0)) + (Math.cbrt(x) * Math.cbrt(x)));
}
function code(x) t_0 = cbrt(Float64(x + 1.0)) return Float64(1.0 / Float64(Float64(Float64(t_0 * t_0) + Float64(cbrt(x) * t_0)) + Float64(cbrt(x) * cbrt(x)))) end
code[x_] := Block[{t$95$0 = N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision]}, N[(1.0 / N[(N[(N[(t$95$0 * t$95$0), $MachinePrecision] + N[(N[Power[x, 1/3], $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(N[Power[x, 1/3], $MachinePrecision] * N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{x + 1}\\
\frac{1}{\left(t\_0 \cdot t\_0 + \sqrt[3]{x} \cdot t\_0\right) + \sqrt[3]{x} \cdot \sqrt[3]{x}}
\end{array}
\end{array}
herbie shell --seed 2024048
(FPCore (x)
:name "2cbrt (problem 3.3.4)"
:precision binary64
:pre (and (> x 1.0) (< x 1e+308))
:alt
(/ 1.0 (+ (+ (* (cbrt (+ x 1.0)) (cbrt (+ x 1.0))) (* (cbrt x) (cbrt (+ x 1.0)))) (* (cbrt x) (cbrt x))))
(- (cbrt (+ x 1.0)) (cbrt x)))