Average Error: 37.5 → 13.3
Time: 2.4m
Precision: 64
Internal Precision: 2368
\[\tan \left(x + \varepsilon\right) - \tan x\]
\[-\left(\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)} + \log \left(e^{\frac{\sin x}{\cos x} + \frac{\sin x}{(\left(\frac{\sin \varepsilon}{\cos \varepsilon}\right) \cdot \left(\sin x\right) + \left(-\cos x\right))_*}}\right)\right)\]

Error

Bits error versus x

Bits error versus eps

Target

Original37.5
Target15.2
Herbie13.3
\[\frac{\sin \varepsilon}{\cos x \cdot \cos \left(x + \varepsilon\right)}\]

Derivation

  1. Initial program 37.5

    \[\tan \left(x + \varepsilon\right) - \tan x\]
  2. Using strategy rm
  3. Applied tan-sum22.3

    \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x\]
  4. Using strategy rm
  5. Applied frac-2neg22.3

    \[\leadsto \color{blue}{\frac{-\left(\tan x + \tan \varepsilon\right)}{-\left(1 - \tan x \cdot \tan \varepsilon\right)}} - \tan x\]
  6. Applied simplify22.2

    \[\leadsto \frac{-\left(\tan x + \tan \varepsilon\right)}{\color{blue}{(\left(\tan \varepsilon\right) \cdot \left(\tan x\right) + \left(-1\right))_*}} - \tan x\]
  7. Taylor expanded around inf 13.3

    \[\leadsto \color{blue}{-\left(\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)} + \left(\frac{\sin x}{\cos x} + \frac{\sin x}{\cos x \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)}\right)\right)}\]
  8. Using strategy rm
  9. Applied add-log-exp22.0

    \[\leadsto -\left(\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)} + \left(\frac{\sin x}{\cos x} + \color{blue}{\log \left(e^{\frac{\sin x}{\cos x \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)}}\right)}\right)\right)\]
  10. Applied add-log-exp15.2

    \[\leadsto -\left(\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)} + \left(\color{blue}{\log \left(e^{\frac{\sin x}{\cos x}}\right)} + \log \left(e^{\frac{\sin x}{\cos x \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)}}\right)\right)\right)\]
  11. Applied sum-log14.3

    \[\leadsto -\left(\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)} + \color{blue}{\log \left(e^{\frac{\sin x}{\cos x}} \cdot e^{\frac{\sin x}{\cos x \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)}}\right)}\right)\]
  12. Applied simplify13.3

    \[\leadsto -\left(\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)} + \log \color{blue}{\left(e^{\frac{\sin x}{(\left(\frac{\sin \varepsilon}{\cos \varepsilon}\right) \cdot \left(\frac{\sin x}{1}\right) + \left(-\cos x\right))_*} + \frac{\sin x}{\cos x}}\right)}\right)\]
  13. Applied simplify13.3

    \[\leadsto -\left(\frac{\sin \varepsilon}{\cos \varepsilon \cdot \left(\frac{\sin x \cdot \sin \varepsilon}{\cos x \cdot \cos \varepsilon} - 1\right)} + \log \left(e^{\color{blue}{\frac{\sin x}{\cos x} + \frac{\sin x}{(\left(\frac{\sin \varepsilon}{\cos \varepsilon}\right) \cdot \left(\sin x\right) + \left(-\cos x\right))_*}}}\right)\right)\]

Runtime

Time bar (total: 2.4m)Debug logProfile

herbie shell --seed 2018296 +o rules:numerics
(FPCore (x eps)
  :name "2tan (problem 3.3.2)"

  :herbie-target
  (/ (sin eps) (* (cos x) (cos (+ x eps))))

  (- (tan (+ x eps)) (tan x)))