Average Error: 9.7 → 0.3
Time: 1.2m
Precision: 64
Internal Precision: 1088
\[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}\]
\[\frac{2}{{x}^{3} - x}\]

Error

Bits error versus x

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Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original9.7
Target0.3
Herbie0.3
\[\frac{2}{x \cdot \left(x \cdot x - 1\right)}\]

Derivation

  1. Initial program 9.7

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}\]
  2. Initial simplification9.7

    \[\leadsto \frac{1}{x + 1} + \left(\frac{1}{x - 1} - \frac{2}{x}\right)\]
  3. Using strategy rm
  4. Applied +-commutative9.7

    \[\leadsto \color{blue}{\left(\frac{1}{x - 1} - \frac{2}{x}\right) + \frac{1}{x + 1}}\]
  5. Using strategy rm
  6. Applied frac-sub25.6

    \[\leadsto \color{blue}{\frac{1 \cdot x - \left(x - 1\right) \cdot 2}{\left(x - 1\right) \cdot x}} + \frac{1}{x + 1}\]
  7. Applied frac-add24.8

    \[\leadsto \color{blue}{\frac{\left(1 \cdot x - \left(x - 1\right) \cdot 2\right) \cdot \left(x + 1\right) + \left(\left(x - 1\right) \cdot x\right) \cdot 1}{\left(\left(x - 1\right) \cdot x\right) \cdot \left(x + 1\right)}}\]
  8. Simplified25.3

    \[\leadsto \frac{\color{blue}{(\left((\left(x - 1\right) \cdot \left(-2\right) + x)_*\right) \cdot \left(x + 1\right) + \left(\left(x - 1\right) \cdot x\right))_*}}{\left(\left(x - 1\right) \cdot x\right) \cdot \left(x + 1\right)}\]
  9. Simplified25.3

    \[\leadsto \frac{(\left((\left(x - 1\right) \cdot \left(-2\right) + x)_*\right) \cdot \left(x + 1\right) + \left(\left(x - 1\right) \cdot x\right))_*}{\color{blue}{\left(x - 1\right) \cdot (x \cdot x + x)_*}}\]
  10. Taylor expanded around 0 0.3

    \[\leadsto \frac{\color{blue}{2}}{\left(x - 1\right) \cdot (x \cdot x + x)_*}\]
  11. Taylor expanded around inf 0.3

    \[\leadsto \frac{2}{\color{blue}{{x}^{3} - x}}\]
  12. Final simplification0.3

    \[\leadsto \frac{2}{{x}^{3} - x}\]

Runtime

Time bar (total: 1.2m)Debug logProfile

herbie shell --seed 2018242 +o rules:numerics
(FPCore (x)
  :name "3frac (problem 3.3.3)"

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

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