Error

Derivation

1. Split input into 2 regimes

2. if x < -1.5738644795251036 or 1.5667946788322475 < x

   1. Initial program 0.0

      \[\frac{x - \sin x}{x - \tan x}\]
   2. Using strategy rm

   3. Applied div-sub0.0

      \[\leadsto \color{blue}{\frac{x}{x - \tan x} - \frac{\sin x}{x - \tan x}}\]
   4. Using strategy rm

   5. Applied add-sqr-sqrt0.1

      \[\leadsto \color{blue}{\sqrt{\frac{x}{x - \tan x}} \cdot \sqrt{\frac{x}{x - \tan x}}} - \frac{\sin x}{x - \tan x}\]

   6. Applied fma-neg0.0

      \[\leadsto \color{blue}{(\left(\sqrt{\frac{x}{x - \tan x}}\right) \cdot \left(\sqrt{\frac{x}{x - \tan x}}\right) + \left(-\frac{\sin x}{x - \tan x}\right))_*}\]

   if -1.5738644795251036 < x < 1.5667946788322475

   1. Initial program 62.4

      \[\frac{x - \sin x}{x - \tan x}\]

   2. Taylor expanded around 0 0.2

      \[\leadsto \color{blue}{\frac{9}{40} \cdot {x}^{2} - \left(\frac{27}{2800} \cdot {x}^{4} + \frac{1}{2}\right)}\]

   3. Simplified0.2

      \[\leadsto \color{blue}{(\left(\frac{9}{40} \cdot x\right) \cdot x + \left((\frac{-27}{2800} \cdot \left({x}^{4}\right) + \frac{-1}{2})_*\right))_*}\]
3. Recombined 2 regimes into one program.

4. Final simplification0.1

   \[\leadsto \begin{array}{l} \mathbf{if}\;x \le -1.5738644795251036 \lor \neg \left(x \le 1.5667946788322475\right):\\ \;\;\;\;(\left(\sqrt{\frac{x}{x - \tan x}}\right) \cdot \left(\sqrt{\frac{x}{x - \tan x}}\right) + \left(\frac{-\sin x}{x - \tan x}\right))_*\\ \mathbf{else}:\\ \;\;\;\;(\left(\frac{9}{40} \cdot x\right) \cdot x + \left((\frac{-27}{2800} \cdot \left({x}^{4}\right) + \frac{-1}{2})_*\right))_*\\ \end{array}\]

Reproduce

herbie shell --seed 2018362 +o rules:numerics
(FPCore (x)
  :name "sintan (problem 3.4.5)"
  (/ (- x (sin x)) (- x (tan x))))

Details

Time bar (total: 44.3s)Debug log