Average Error: 10.1 → 0.3
Time: 1.9m
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

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original10.1
Target0.3
Herbie0.3
\[\frac{2}{x \cdot \left(x \cdot x - 1\right)}\]

Derivation

  1. Initial program 10.1

    \[\left(\frac{1}{x + 1} - \frac{2}{x}\right) + \frac{1}{x - 1}\]
  2. Initial simplification10.1

    \[\leadsto \left(\frac{1}{x - 1} + \frac{1}{x + 1}\right) - \frac{2}{x}\]
  3. Using strategy rm
  4. Applied frac-add26.6

    \[\leadsto \color{blue}{\frac{1 \cdot \left(x + 1\right) + \left(x - 1\right) \cdot 1}{\left(x - 1\right) \cdot \left(x + 1\right)}} - \frac{2}{x}\]
  5. Applied frac-sub25.8

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

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

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

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

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

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

Runtime

Time bar (total: 1.9m)Debug logProfile

herbie shell --seed 2018214 
(FPCore (x)
  :name "3frac (problem 3.3.3)"

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

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