\[{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\left(\frac{1}{3}\right)}\]
Test:
NMSE problem 3.3.4
Bits:
128 bits
Bits error versus x
Time: 9.7 s
Input Error: 21.9
Output Error: 7.4
Log:
Profile: 🕒
\(\frac{1}{\sqrt[3]{\left(1 + x\right) \cdot \left(1 + x\right)} + \sqrt[3]{x} \cdot \left(\sqrt[3]{1 + x} + \sqrt[3]{x}\right)}\)
  1. Started with
    \[{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\left(\frac{1}{3}\right)}\]
    21.9
  2. Applied taylor to get
    \[{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\left(\frac{1}{3}\right)} \leadsto {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\frac{1}{3}}\]
    21.9
  3. Taylor expanded around 0 to get
    \[{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - \color{red}{{x}^{\frac{1}{3}}} \leadsto {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - \color{blue}{{x}^{\frac{1}{3}}}\]
    21.9
  4. Applied simplify to get
    \[\color{red}{{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\frac{1}{3}}} \leadsto \color{blue}{{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - \sqrt[3]{x}}\]
    14.2
  5. Using strategy rm
    14.2
  6. Applied flip3-- to get
    \[\color{red}{{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - \sqrt[3]{x}} \leadsto \color{blue}{\frac{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^{3} - {\left(\sqrt[3]{x}\right)}^{3}}{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}}\]
    14.2
  7. Applied simplify to get
    \[\frac{\color{red}{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^{3} - {\left(\sqrt[3]{x}\right)}^{3}}}{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)} \leadsto \frac{\color{blue}{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^3 - x}}{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}\]
    14.2
  8. Using strategy rm
    14.2
  9. Applied add-cube-cbrt to get
    \[\frac{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^3 - x}{\color{red}{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}} \leadsto \frac{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^3 - x}{\color{blue}{{\left(\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}\right)}^3}}\]
    14.4
  10. Applied add-cube-cbrt to get
    \[\frac{\color{red}{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^3 - x}}{{\left(\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}\right)}^3} \leadsto \frac{\color{blue}{{\left(\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^3 - x}\right)}^3}}{{\left(\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}\right)}^3}\]
    14.4
  11. Applied cube-undiv to get
    \[\color{red}{\frac{{\left(\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^3 - x}\right)}^3}{{\left(\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}\right)}^3}} \leadsto \color{blue}{{\left(\frac{\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^3 - x}}{\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}}\right)}^3}\]
    14.4
  12. Applied taylor to get
    \[{\left(\frac{\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^3 - x}}{\sqrt[3]{{\left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)}\right)}^2 + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} \cdot \sqrt[3]{x}\right)}}\right)}^3 \leadsto {\left(\frac{\sqrt[3]{{\left({\left(1 + x\right)}^{\frac{1}{3}}\right)}^3 - x}}{\sqrt[3]{{\left({\left(1 + x\right)}^2\right)}^{\frac{1}{3}} + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(1 + x\right)}^{\frac{1}{3}} \cdot \sqrt[3]{x}\right)}}\right)}^3\]
    14.4
  13. Taylor expanded around 0 to get
    \[\color{red}{{\left(\frac{\sqrt[3]{{\left({\left(1 + x\right)}^{\frac{1}{3}}\right)}^3 - x}}{\sqrt[3]{{\left({\left(1 + x\right)}^2\right)}^{\frac{1}{3}} + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(1 + x\right)}^{\frac{1}{3}} \cdot \sqrt[3]{x}\right)}}\right)}^3} \leadsto \color{blue}{{\left(\frac{\sqrt[3]{{\left({\left(1 + x\right)}^{\frac{1}{3}}\right)}^3 - x}}{\sqrt[3]{{\left({\left(1 + x\right)}^2\right)}^{\frac{1}{3}} + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(1 + x\right)}^{\frac{1}{3}} \cdot \sqrt[3]{x}\right)}}\right)}^3}\]
    14.4
  14. Applied simplify to get
    \[{\left(\frac{\sqrt[3]{{\left({\left(1 + x\right)}^{\frac{1}{3}}\right)}^3 - x}}{\sqrt[3]{{\left({\left(1 + x\right)}^2\right)}^{\frac{1}{3}} + \left({\left(\sqrt[3]{x}\right)}^2 + {\left(1 + x\right)}^{\frac{1}{3}} \cdot \sqrt[3]{x}\right)}}\right)}^3 \leadsto \frac{\left(1 + x\right) - x}{\sqrt[3]{x} \cdot \left(\sqrt[3]{1 + x} + \sqrt[3]{x}\right) + \sqrt[3]{\left(1 + x\right) \cdot \left(1 + x\right)}}\]
    12.0

  15. Applied final simplification
  16. Applied simplify to get
    \[\color{red}{\frac{\left(1 + x\right) - x}{\sqrt[3]{x} \cdot \left(\sqrt[3]{1 + x} + \sqrt[3]{x}\right) + \sqrt[3]{\left(1 + x\right) \cdot \left(1 + x\right)}}} \leadsto \color{blue}{\frac{1}{\sqrt[3]{\left(1 + x\right) \cdot \left(1 + x\right)} + \sqrt[3]{x} \cdot \left(\sqrt[3]{1 + x} + \sqrt[3]{x}\right)}}\]
    7.4

Original test:


(lambda ((x default))
  #:name "NMSE problem 3.3.4"
  (- (pow (+ x 1) (/ 1 3)) (pow x (/ 1 3))))