Average Error: 9.5 → 0.1
Time: 1.1m
Precision: 64
Internal precision: 1152
\[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}\]
\[\frac{\frac{2}{x}}{1 - {x}^2} \cdot \frac{1 - x}{x - 1}\]

Error

Bits error versus x

Target

Original9.5
Comparison0.2
Herbie0.1
\[ \frac{2}{x \cdot \left({x}^2 - 1\right)} \]

Derivation

  1. Initial program 9.5

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}\]
  2. Using strategy rm
  3. Applied frac-sub 26.1

    \[\leadsto \color{blue}{\frac{1 \cdot x - \left(x + 1\right) \cdot 2}{\left(x + 1\right) \cdot x}} + \frac{1}{x - 1}\]
  4. Applied frac-add 25.4

    \[\leadsto \color{blue}{\frac{\left(1 \cdot x - \left(x + 1\right) \cdot 2\right) \cdot \left(x - 1\right) + \left(\left(x + 1\right) \cdot x\right) \cdot 1}{\left(\left(x + 1\right) \cdot x\right) \cdot \left(x - 1\right)}}\]
  5. Applied simplify 25.5

    \[\leadsto \frac{\color{blue}{\left(\left(x - 2\right) - \left(x + x\right)\right) \cdot \left(x - 1\right) + \left(x + x \cdot x\right)}}{\left(\left(x + 1\right) \cdot x\right) \cdot \left(x - 1\right)}\]
  6. Applied taylor 25.4

    \[\leadsto \frac{\left(2 - \left(x + {x}^2\right)\right) + \left(x + x \cdot x\right)}{\left(\left(x + 1\right) \cdot x\right) \cdot \left(x - 1\right)}\]
  7. Taylor expanded around 0 25.4

    \[\leadsto \frac{\color{blue}{\left(2 - \left(x + {x}^2\right)\right)} + \left(x + x \cdot x\right)}{\left(\left(x + 1\right) \cdot x\right) \cdot \left(x - 1\right)}\]
  8. Applied simplify 0.1

    \[\leadsto \color{blue}{\frac{\frac{\frac{2}{x}}{1 + x}}{x - 1}}\]
  9. Using strategy rm
  10. Applied *-un-lft-identity 0.1

    \[\leadsto \frac{\frac{\frac{2}{x}}{1 + x}}{\color{blue}{1 \cdot \left(x - 1\right)}}\]
  11. Applied flip-+ 0.1

    \[\leadsto \frac{\frac{\frac{2}{x}}{\color{blue}{\frac{{1}^2 - {x}^2}{1 - x}}}}{1 \cdot \left(x - 1\right)}\]
  12. Applied associate-/r/ 0.1

    \[\leadsto \frac{\color{blue}{\frac{\frac{2}{x}}{{1}^2 - {x}^2} \cdot \left(1 - x\right)}}{1 \cdot \left(x - 1\right)}\]
  13. Applied times-frac 0.1

    \[\leadsto \color{blue}{\frac{\frac{\frac{2}{x}}{{1}^2 - {x}^2}}{1} \cdot \frac{1 - x}{x - 1}}\]
  14. Applied simplify 0.1

    \[\leadsto \color{blue}{\frac{\frac{2}{x}}{1 - {x}^2}} \cdot \frac{1 - x}{x - 1}\]
  15. Removed slow pow expressions

Runtime

Time bar (total: 1.1m) Debug log

Please include this information when filing a bug report:

herbie shell --seed '#(3283856077 3183919125 3399458751 396155847 3688194147 1862413033)'
(FPCore (x)
  :name "3frac (problem 3.3.3)"

  :target
  (/ 2 (* x (- (sqr x) 1)))

  (+ (- (/ 1 (+ x 1)) (/ 2 x)) (/ 1 (- x 1))))