Average Error: 29.7 → 0.6
Time: 4.6s
Precision: binary64
\[\sqrt[3]{x + 1} - \sqrt[3]{x} \]
↓
\[\begin{array}{l} t_0 := \sqrt[3]{1 + x}\\ t_1 := \sqrt[3]{\sqrt[3]{x}}\\ \frac{1}{t_0 \cdot t_0 + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + t_0 \cdot \sqrt[3]{\sqrt[3]{x} \cdot \left(\left(t_1 \cdot t_1\right) \cdot \left(\sqrt[3]{x} \cdot t_1\right)\right)}\right)} \end{array} \]
\sqrt[3]{x + 1} - \sqrt[3]{x}
↓
\begin{array}{l}
t_0 := \sqrt[3]{1 + x}\\
t_1 := \sqrt[3]{\sqrt[3]{x}}\\
\frac{1}{t_0 \cdot t_0 + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + t_0 \cdot \sqrt[3]{\sqrt[3]{x} \cdot \left(\left(t_1 \cdot t_1\right) \cdot \left(\sqrt[3]{x} \cdot t_1\right)\right)}\right)}
\end{array}

(FPCore (x) :precision binary64 (- (cbrt (+ x 1.0)) (cbrt x)))
↓
(FPCore (x)
 :precision binary64
 (let* ((t_0 (cbrt (+ 1.0 x))) (t_1 (cbrt (cbrt x))))
   (/
    1.0
    (+
     (* t_0 t_0)
     (+
      (* (cbrt x) (cbrt x))
      (* t_0 (cbrt (* (cbrt x) (* (* t_1 t_1) (* (cbrt x) t_1))))))))))
double code(double x) {
	return cbrt(x + 1.0) - cbrt(x);
}
↓
double code(double x) {
	double t_0 = cbrt(1.0 + x);
	double t_1 = cbrt(cbrt(x));
	return 1.0 / ((t_0 * t_0) + ((cbrt(x) * cbrt(x)) + (t_0 * cbrt(cbrt(x) * ((t_1 * t_1) * (cbrt(x) * t_1))))));
}

Error

Bits error versus x

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Initial program 29.7

    \[\sqrt[3]{x + 1} - \sqrt[3]{x} \]

  2. Applied flip3--_binary6429.7

    \[\leadsto \color{blue}{\frac{{\left(\sqrt[3]{x + 1}\right)}^{3} - {\left(\sqrt[3]{x}\right)}^{3}}{\sqrt[3]{x + 1} \cdot \sqrt[3]{x + 1} + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + \sqrt[3]{x + 1} \cdot \sqrt[3]{x}\right)}} \]

  3. Taylor expanded in x around 0 0.5

    \[\leadsto \frac{\color{blue}{1}}{\sqrt[3]{x + 1} \cdot \sqrt[3]{x + 1} + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + \sqrt[3]{x + 1} \cdot \sqrt[3]{x}\right)} \]

  4. Applied add-cbrt-cube_binary640.5

    \[\leadsto \frac{1}{\sqrt[3]{x + 1} \cdot \sqrt[3]{x + 1} + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + \sqrt[3]{x + 1} \cdot \color{blue}{\sqrt[3]{\left(\sqrt[3]{x} \cdot \sqrt[3]{x}\right) \cdot \sqrt[3]{x}}}\right)} \]

  5. Applied add-cube-cbrt_binary640.6

    \[\leadsto \frac{1}{\sqrt[3]{x + 1} \cdot \sqrt[3]{x + 1} + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + \sqrt[3]{x + 1} \cdot \sqrt[3]{\left(\color{blue}{\left(\left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{\sqrt[3]{x}}\right) \cdot \sqrt[3]{\sqrt[3]{x}}\right)} \cdot \sqrt[3]{x}\right) \cdot \sqrt[3]{x}}\right)} \]

  6. Applied associate-*l*_binary640.6

    \[\leadsto \frac{1}{\sqrt[3]{x + 1} \cdot \sqrt[3]{x + 1} + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + \sqrt[3]{x + 1} \cdot \sqrt[3]{\color{blue}{\left(\left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{\sqrt[3]{x}}\right) \cdot \left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{x}\right)\right)} \cdot \sqrt[3]{x}}\right)} \]

  7. Final simplification0.6

    \[\leadsto \frac{1}{\sqrt[3]{1 + x} \cdot \sqrt[3]{1 + x} + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + \sqrt[3]{1 + x} \cdot \sqrt[3]{\sqrt[3]{x} \cdot \left(\left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{\sqrt[3]{x}}\right) \cdot \left(\sqrt[3]{x} \cdot \sqrt[3]{\sqrt[3]{x}}\right)\right)}\right)} \]

Reproduce

herbie shell --seed 2021307 
(FPCore (x)
  :name "2cbrt (problem 3.3.4)"
  :precision binary64
  (- (cbrt (+ x 1.0)) (cbrt x)))