VandenBroeck and Keller, Equation (20)

Percentage Accurate: 6.7% → 97.0%
Time: 33.9s
Alternatives: 8
Speedup: TODO×

Specification

?
\[\begin{array}{l} t_0 := \frac{\pi}{4}\\ t_1 := t_0 \cdot f\\ t_2 := e^{t_1}\\ t_3 := e^{-t_1}\\ -\frac{1}{t_0} \cdot \log \left(\frac{t_2 + t_3}{t_2 - t_3}\right) \end{array} \]

Your Program's Arguments

Results

Enter valid numbers for all inputs

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 8 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Alternative 1?

\[\begin{array}{l} t_0 := f \cdot \left(\pi \cdot 0.25\right)\\ 1 - \left(1 + \frac{\log \left(\frac{\cosh t_0}{\sinh t_0}\right)}{\pi \cdot 0.25}\right) \end{array} \]
Derivation
  1. Initial program 7.9%

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
  2. Step-by-step derivation
    1. expm1-log1p-u7.9%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
    2. expm1-udef7.9%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} - 1\right)} \]
  3. Applied egg-rr96.1%

    \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  4. Step-by-step derivation
    1. expm1-def96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    2. expm1-log1p97.4%

      \[\leadsto -\color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}} \]
    3. times-frac97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2}{2} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    4. metadata-eval97.4%

      \[\leadsto -\frac{\log \left(\color{blue}{1} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    5. *-lft-identity97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    6. associate-/l*97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    7. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    8. associate-/l*97.1%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}\right)}{\pi \cdot 0.25} \]
    9. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}\right)}{\pi \cdot 0.25} \]
    10. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{\color{blue}{0.25 \cdot \pi}} \]
  5. Simplified97.4%

    \[\leadsto -\color{blue}{\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi}} \]
  6. Step-by-step derivation
    1. cosh-def97.4%

      \[\leadsto -\frac{\log \left(\frac{\color{blue}{\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{2}}}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    2. cosh-undef97.4%

      \[\leadsto -\frac{\log \left(\frac{\frac{\color{blue}{2 \cdot \cosh \left(\frac{\pi}{4} \cdot f\right)}}{2}}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    3. associate-*l/97.4%

      \[\leadsto -\frac{\log \left(\frac{\frac{2 \cdot \cosh \color{blue}{\left(\frac{\pi \cdot f}{4}\right)}}{2}}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    4. associate-*l/97.4%

      \[\leadsto -\frac{\log \left(\frac{\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2}}{\sinh \color{blue}{\left(\frac{\pi \cdot f}{4}\right)}}\right)}{0.25 \cdot \pi} \]
    5. associate-/r*97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{0.25 \cdot \pi} \]
    6. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\color{blue}{\pi \cdot 0.25}} \]
    7. expm1-log1p-u96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    8. expm1-udef96.1%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  7. Applied egg-rr97.5%

    \[\leadsto -\color{blue}{\left(\left(1 + \frac{\log \left(\frac{\cosh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}\right)}{\pi \cdot 0.25}\right) - 1\right)} \]
  8. Final simplification97.5%

    \[\leadsto 1 - \left(1 + \frac{\log \left(\frac{\cosh \left(f \cdot \left(\pi \cdot 0.25\right)\right)}{\sinh \left(f \cdot \left(\pi \cdot 0.25\right)\right)}\right)}{\pi \cdot 0.25}\right) \]

Alternative 2?

\[\begin{array}{l} t_0 := 0.25 \cdot \left(\pi \cdot f\right)\\ \log \left(\frac{\sinh t_0}{\cosh t_0}\right) \cdot \frac{--4}{\pi} \end{array} \]
Derivation
  1. Initial program 7.9%

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
  2. Step-by-step derivation
    1. expm1-log1p-u7.9%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
    2. expm1-udef7.9%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} - 1\right)} \]
  3. Applied egg-rr96.1%

    \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  4. Step-by-step derivation
    1. expm1-def96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    2. expm1-log1p97.4%

      \[\leadsto -\color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}} \]
    3. times-frac97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2}{2} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    4. metadata-eval97.4%

      \[\leadsto -\frac{\log \left(\color{blue}{1} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    5. *-lft-identity97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    6. associate-/l*97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    7. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    8. associate-/l*97.1%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}\right)}{\pi \cdot 0.25} \]
    9. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}\right)}{\pi \cdot 0.25} \]
    10. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{\color{blue}{0.25 \cdot \pi}} \]
  5. Simplified97.4%

    \[\leadsto -\color{blue}{\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi}} \]
  6. Step-by-step derivation
    1. clear-num97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{1}{\frac{\sinh \left(\frac{\pi}{4} \cdot f\right)}{\cosh \left(\frac{\pi}{4} \cdot f\right)}}\right)}}{0.25 \cdot \pi} \]
    2. log-rec97.5%

      \[\leadsto -\frac{\color{blue}{-\log \left(\frac{\sinh \left(\frac{\pi}{4} \cdot f\right)}{\cosh \left(\frac{\pi}{4} \cdot f\right)}\right)}}{0.25 \cdot \pi} \]
    3. div-inv97.5%

      \[\leadsto -\frac{-\log \left(\frac{\sinh \left(\color{blue}{\left(\pi \cdot \frac{1}{4}\right)} \cdot f\right)}{\cosh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    4. metadata-eval97.5%

      \[\leadsto -\frac{-\log \left(\frac{\sinh \left(\left(\pi \cdot \color{blue}{0.25}\right) \cdot f\right)}{\cosh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    5. div-inv97.5%

      \[\leadsto -\frac{-\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\color{blue}{\left(\pi \cdot \frac{1}{4}\right)} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    6. metadata-eval97.5%

      \[\leadsto -\frac{-\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\left(\pi \cdot \color{blue}{0.25}\right) \cdot f\right)}\right)}{0.25 \cdot \pi} \]
  7. Applied egg-rr97.5%

    \[\leadsto -\frac{\color{blue}{-\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}\right)}}{0.25 \cdot \pi} \]
  8. Step-by-step derivation
    1. distribute-frac-neg97.5%

      \[\leadsto -\color{blue}{\left(-\frac{\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}\right)}{0.25 \cdot \pi}\right)} \]
    2. neg-sub097.5%

      \[\leadsto -\color{blue}{\left(0 - \frac{\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}\right)}{0.25 \cdot \pi}\right)} \]
    3. add-sqr-sqrt0.0%

      \[\leadsto -\left(0 - \frac{\color{blue}{\sqrt{\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}\right)} \cdot \sqrt{\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}\right)}}}{0.25 \cdot \pi}\right) \]
  9. Applied egg-rr79.2%

    \[\leadsto -\color{blue}{\left(0 - \log \left({\left(\frac{\sinh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}{\cosh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}\right)}^{\left(\frac{4}{\pi}\right)}\right)\right)} \]
  10. Step-by-step derivation
    1. neg-sub079.2%

      \[\leadsto -\color{blue}{\left(-\log \left({\left(\frac{\sinh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}{\cosh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}\right)}^{\left(\frac{4}{\pi}\right)}\right)\right)} \]
    2. log-pow97.4%

      \[\leadsto -\left(-\color{blue}{\frac{4}{\pi} \cdot \log \left(\frac{\sinh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}{\cosh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}\right)}\right) \]
    3. *-commutative97.4%

      \[\leadsto -\left(-\color{blue}{\log \left(\frac{\sinh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}{\cosh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}\right) \cdot \frac{4}{\pi}}\right) \]
    4. distribute-rgt-neg-in97.4%

      \[\leadsto -\color{blue}{\log \left(\frac{\sinh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}{\cosh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}\right) \cdot \left(-\frac{4}{\pi}\right)} \]
    5. *-commutative97.4%

      \[\leadsto -\log \left(\frac{\sinh \color{blue}{\left(\left(0.25 \cdot f\right) \cdot \pi\right)}}{\cosh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}\right) \cdot \left(-\frac{4}{\pi}\right) \]
    6. associate-*r*97.4%

      \[\leadsto -\log \left(\frac{\sinh \color{blue}{\left(0.25 \cdot \left(f \cdot \pi\right)\right)}}{\cosh \left(\pi \cdot \left(0.25 \cdot f\right)\right)}\right) \cdot \left(-\frac{4}{\pi}\right) \]
    7. *-commutative97.4%

      \[\leadsto -\log \left(\frac{\sinh \left(0.25 \cdot \left(f \cdot \pi\right)\right)}{\cosh \color{blue}{\left(\left(0.25 \cdot f\right) \cdot \pi\right)}}\right) \cdot \left(-\frac{4}{\pi}\right) \]
    8. associate-*r*97.4%

      \[\leadsto -\log \left(\frac{\sinh \left(0.25 \cdot \left(f \cdot \pi\right)\right)}{\cosh \color{blue}{\left(0.25 \cdot \left(f \cdot \pi\right)\right)}}\right) \cdot \left(-\frac{4}{\pi}\right) \]
    9. distribute-neg-frac97.4%

      \[\leadsto -\log \left(\frac{\sinh \left(0.25 \cdot \left(f \cdot \pi\right)\right)}{\cosh \left(0.25 \cdot \left(f \cdot \pi\right)\right)}\right) \cdot \color{blue}{\frac{-4}{\pi}} \]
    10. metadata-eval97.4%

      \[\leadsto -\log \left(\frac{\sinh \left(0.25 \cdot \left(f \cdot \pi\right)\right)}{\cosh \left(0.25 \cdot \left(f \cdot \pi\right)\right)}\right) \cdot \frac{\color{blue}{-4}}{\pi} \]
  11. Simplified97.4%

    \[\leadsto -\color{blue}{\log \left(\frac{\sinh \left(0.25 \cdot \left(f \cdot \pi\right)\right)}{\cosh \left(0.25 \cdot \left(f \cdot \pi\right)\right)}\right) \cdot \frac{-4}{\pi}} \]
  12. Final simplification97.4%

    \[\leadsto \log \left(\frac{\sinh \left(0.25 \cdot \left(\pi \cdot f\right)\right)}{\cosh \left(0.25 \cdot \left(\pi \cdot f\right)\right)}\right) \cdot \frac{--4}{\pi} \]

Alternative 3?

\[\begin{array}{l} t_0 := f \cdot \frac{\pi}{4}\\ \frac{-\log \left(\frac{\cosh t_0}{\sinh t_0}\right)}{\pi \cdot 0.25} \end{array} \]
Derivation
  1. Initial program 7.9%

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
  2. Step-by-step derivation
    1. expm1-log1p-u7.9%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
    2. expm1-udef7.9%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} - 1\right)} \]
  3. Applied egg-rr96.1%

    \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  4. Step-by-step derivation
    1. expm1-def96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    2. expm1-log1p97.4%

      \[\leadsto -\color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}} \]
    3. times-frac97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2}{2} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    4. metadata-eval97.4%

      \[\leadsto -\frac{\log \left(\color{blue}{1} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    5. *-lft-identity97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    6. associate-/l*97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    7. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    8. associate-/l*97.1%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}\right)}{\pi \cdot 0.25} \]
    9. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}\right)}{\pi \cdot 0.25} \]
    10. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{\color{blue}{0.25 \cdot \pi}} \]
  5. Simplified97.4%

    \[\leadsto -\color{blue}{\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi}} \]
  6. Final simplification97.4%

    \[\leadsto \frac{-\log \left(\frac{\cosh \left(f \cdot \frac{\pi}{4}\right)}{\sinh \left(f \cdot \frac{\pi}{4}\right)}\right)}{\pi \cdot 0.25} \]

Alternative 4?

\[\begin{array}{l} t_0 := f \cdot \left(\pi \cdot 0.25\right)\\ \frac{\log \left(\frac{\sinh t_0}{\cosh t_0}\right)}{\pi \cdot 0.25} \end{array} \]
Derivation
  1. Initial program 7.9%

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
  2. Step-by-step derivation
    1. expm1-log1p-u7.9%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
    2. expm1-udef7.9%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} - 1\right)} \]
  3. Applied egg-rr96.1%

    \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  4. Step-by-step derivation
    1. expm1-def96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    2. expm1-log1p97.4%

      \[\leadsto -\color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}} \]
    3. times-frac97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2}{2} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    4. metadata-eval97.4%

      \[\leadsto -\frac{\log \left(\color{blue}{1} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    5. *-lft-identity97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    6. associate-/l*97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    7. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    8. associate-/l*97.1%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}\right)}{\pi \cdot 0.25} \]
    9. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}\right)}{\pi \cdot 0.25} \]
    10. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{\color{blue}{0.25 \cdot \pi}} \]
  5. Simplified97.4%

    \[\leadsto -\color{blue}{\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi}} \]
  6. Step-by-step derivation
    1. clear-num97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{1}{\frac{\sinh \left(\frac{\pi}{4} \cdot f\right)}{\cosh \left(\frac{\pi}{4} \cdot f\right)}}\right)}}{0.25 \cdot \pi} \]
    2. log-rec97.5%

      \[\leadsto -\frac{\color{blue}{-\log \left(\frac{\sinh \left(\frac{\pi}{4} \cdot f\right)}{\cosh \left(\frac{\pi}{4} \cdot f\right)}\right)}}{0.25 \cdot \pi} \]
    3. div-inv97.5%

      \[\leadsto -\frac{-\log \left(\frac{\sinh \left(\color{blue}{\left(\pi \cdot \frac{1}{4}\right)} \cdot f\right)}{\cosh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    4. metadata-eval97.5%

      \[\leadsto -\frac{-\log \left(\frac{\sinh \left(\left(\pi \cdot \color{blue}{0.25}\right) \cdot f\right)}{\cosh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    5. div-inv97.5%

      \[\leadsto -\frac{-\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\color{blue}{\left(\pi \cdot \frac{1}{4}\right)} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    6. metadata-eval97.5%

      \[\leadsto -\frac{-\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\left(\pi \cdot \color{blue}{0.25}\right) \cdot f\right)}\right)}{0.25 \cdot \pi} \]
  7. Applied egg-rr97.5%

    \[\leadsto -\frac{\color{blue}{-\log \left(\frac{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\cosh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}\right)}}{0.25 \cdot \pi} \]
  8. Final simplification97.5%

    \[\leadsto \frac{\log \left(\frac{\sinh \left(f \cdot \left(\pi \cdot 0.25\right)\right)}{\cosh \left(f \cdot \left(\pi \cdot 0.25\right)\right)}\right)}{\pi \cdot 0.25} \]

Alternative 5?

\[\frac{-\left|\log \left(\frac{4}{\pi \cdot f}\right)\right|}{\pi \cdot 0.25} \]
Derivation
  1. Initial program 7.9%

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
  2. Step-by-step derivation
    1. expm1-log1p-u7.9%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
    2. expm1-udef7.9%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} - 1\right)} \]
  3. Applied egg-rr96.1%

    \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  4. Step-by-step derivation
    1. expm1-def96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    2. expm1-log1p97.4%

      \[\leadsto -\color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}} \]
    3. times-frac97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2}{2} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    4. metadata-eval97.4%

      \[\leadsto -\frac{\log \left(\color{blue}{1} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    5. *-lft-identity97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    6. associate-/l*97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    7. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    8. associate-/l*97.1%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}\right)}{\pi \cdot 0.25} \]
    9. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}\right)}{\pi \cdot 0.25} \]
    10. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{\color{blue}{0.25 \cdot \pi}} \]
  5. Simplified97.4%

    \[\leadsto -\color{blue}{\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi}} \]
  6. Taylor expanded in f around 0 96.1%

    \[\leadsto -\frac{\log \color{blue}{\left(\frac{4}{f \cdot \pi}\right)}}{0.25 \cdot \pi} \]
  7. Step-by-step derivation
    1. add-sqr-sqrt95.6%

      \[\leadsto -\frac{\color{blue}{\sqrt{\log \left(\frac{4}{f \cdot \pi}\right)} \cdot \sqrt{\log \left(\frac{4}{f \cdot \pi}\right)}}}{0.25 \cdot \pi} \]
    2. sqrt-unprod96.2%

      \[\leadsto -\frac{\color{blue}{\sqrt{\log \left(\frac{4}{f \cdot \pi}\right) \cdot \log \left(\frac{4}{f \cdot \pi}\right)}}}{0.25 \cdot \pi} \]
    3. pow296.2%

      \[\leadsto -\frac{\sqrt{\color{blue}{{\log \left(\frac{4}{f \cdot \pi}\right)}^{2}}}}{0.25 \cdot \pi} \]
    4. *-commutative96.2%

      \[\leadsto -\frac{\sqrt{{\log \left(\frac{4}{\color{blue}{\pi \cdot f}}\right)}^{2}}}{0.25 \cdot \pi} \]
  8. Applied egg-rr96.2%

    \[\leadsto -\frac{\color{blue}{\sqrt{{\log \left(\frac{4}{\pi \cdot f}\right)}^{2}}}}{0.25 \cdot \pi} \]
  9. Step-by-step derivation
    1. unpow296.2%

      \[\leadsto -\frac{\sqrt{\color{blue}{\log \left(\frac{4}{\pi \cdot f}\right) \cdot \log \left(\frac{4}{\pi \cdot f}\right)}}}{0.25 \cdot \pi} \]
    2. rem-sqrt-square96.2%

      \[\leadsto -\frac{\color{blue}{\left|\log \left(\frac{4}{\pi \cdot f}\right)\right|}}{0.25 \cdot \pi} \]
    3. *-commutative96.2%

      \[\leadsto -\frac{\left|\log \left(\frac{4}{\color{blue}{f \cdot \pi}}\right)\right|}{0.25 \cdot \pi} \]
  10. Simplified96.2%

    \[\leadsto -\frac{\color{blue}{\left|\log \left(\frac{4}{f \cdot \pi}\right)\right|}}{0.25 \cdot \pi} \]
  11. Final simplification96.2%

    \[\leadsto \frac{-\left|\log \left(\frac{4}{\pi \cdot f}\right)\right|}{\pi \cdot 0.25} \]

Alternative 6?

\[1 + \left(-1 - \frac{\log \left(\frac{4}{\pi \cdot f}\right)}{\pi \cdot 0.25}\right) \]
Derivation
  1. Initial program 7.9%

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
  2. Step-by-step derivation
    1. expm1-log1p-u7.9%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
    2. expm1-udef7.9%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} - 1\right)} \]
  3. Applied egg-rr96.1%

    \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  4. Step-by-step derivation
    1. expm1-def96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    2. expm1-log1p97.4%

      \[\leadsto -\color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}} \]
    3. times-frac97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2}{2} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    4. metadata-eval97.4%

      \[\leadsto -\frac{\log \left(\color{blue}{1} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    5. *-lft-identity97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    6. associate-/l*97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    7. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    8. associate-/l*97.1%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}\right)}{\pi \cdot 0.25} \]
    9. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}\right)}{\pi \cdot 0.25} \]
    10. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{\color{blue}{0.25 \cdot \pi}} \]
  5. Simplified97.4%

    \[\leadsto -\color{blue}{\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi}} \]
  6. Step-by-step derivation
    1. cosh-def97.4%

      \[\leadsto -\frac{\log \left(\frac{\color{blue}{\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{2}}}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    2. cosh-undef97.4%

      \[\leadsto -\frac{\log \left(\frac{\frac{\color{blue}{2 \cdot \cosh \left(\frac{\pi}{4} \cdot f\right)}}{2}}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    3. associate-*l/97.4%

      \[\leadsto -\frac{\log \left(\frac{\frac{2 \cdot \cosh \color{blue}{\left(\frac{\pi \cdot f}{4}\right)}}{2}}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi} \]
    4. associate-*l/97.4%

      \[\leadsto -\frac{\log \left(\frac{\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2}}{\sinh \color{blue}{\left(\frac{\pi \cdot f}{4}\right)}}\right)}{0.25 \cdot \pi} \]
    5. associate-/r*97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{0.25 \cdot \pi} \]
    6. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\color{blue}{\pi \cdot 0.25}} \]
    7. expm1-log1p-u96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    8. expm1-udef96.1%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  7. Applied egg-rr97.5%

    \[\leadsto -\color{blue}{\left(\left(1 + \frac{\log \left(\frac{\cosh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}{\sinh \left(\left(\pi \cdot 0.25\right) \cdot f\right)}\right)}{\pi \cdot 0.25}\right) - 1\right)} \]
  8. Taylor expanded in f around 0 96.1%

    \[\leadsto -\left(\left(1 + \frac{\log \color{blue}{\left(\frac{4}{f \cdot \pi}\right)}}{\pi \cdot 0.25}\right) - 1\right) \]
  9. Final simplification96.1%

    \[\leadsto 1 + \left(-1 - \frac{\log \left(\frac{4}{\pi \cdot f}\right)}{\pi \cdot 0.25}\right) \]

Alternative 7?

\[\log \left(\frac{4}{\pi \cdot f}\right) \cdot \frac{-4}{\pi} \]
Derivation
  1. Initial program 7.9%

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
  2. Step-by-step derivation
    1. expm1-log1p-u7.9%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
    2. expm1-udef7.9%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} - 1\right)} \]
  3. Applied egg-rr96.1%

    \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  4. Step-by-step derivation
    1. expm1-def96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    2. expm1-log1p97.4%

      \[\leadsto -\color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}} \]
    3. times-frac97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2}{2} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    4. metadata-eval97.4%

      \[\leadsto -\frac{\log \left(\color{blue}{1} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    5. *-lft-identity97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    6. associate-/l*97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    7. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    8. associate-/l*97.1%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}\right)}{\pi \cdot 0.25} \]
    9. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}\right)}{\pi \cdot 0.25} \]
    10. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{\color{blue}{0.25 \cdot \pi}} \]
  5. Simplified97.4%

    \[\leadsto -\color{blue}{\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi}} \]
  6. Taylor expanded in f around 0 96.1%

    \[\leadsto -\frac{\log \color{blue}{\left(\frac{4}{f \cdot \pi}\right)}}{0.25 \cdot \pi} \]
  7. Step-by-step derivation
    1. div-inv96.0%

      \[\leadsto -\color{blue}{\log \left(\frac{4}{f \cdot \pi}\right) \cdot \frac{1}{0.25 \cdot \pi}} \]
    2. *-commutative96.0%

      \[\leadsto -\log \left(\frac{4}{\color{blue}{\pi \cdot f}}\right) \cdot \frac{1}{0.25 \cdot \pi} \]
    3. *-commutative96.0%

      \[\leadsto -\log \left(\frac{4}{\pi \cdot f}\right) \cdot \frac{1}{\color{blue}{\pi \cdot 0.25}} \]
    4. inv-pow96.0%

      \[\leadsto -\log \left(\frac{4}{\pi \cdot f}\right) \cdot \color{blue}{{\left(\pi \cdot 0.25\right)}^{-1}} \]
    5. *-commutative96.0%

      \[\leadsto -\log \left(\frac{4}{\pi \cdot f}\right) \cdot {\color{blue}{\left(0.25 \cdot \pi\right)}}^{-1} \]
    6. unpow-prod-down96.0%

      \[\leadsto -\log \left(\frac{4}{\pi \cdot f}\right) \cdot \color{blue}{\left({0.25}^{-1} \cdot {\pi}^{-1}\right)} \]
    7. metadata-eval96.0%

      \[\leadsto -\log \left(\frac{4}{\pi \cdot f}\right) \cdot \left(\color{blue}{4} \cdot {\pi}^{-1}\right) \]
    8. inv-pow96.0%

      \[\leadsto -\log \left(\frac{4}{\pi \cdot f}\right) \cdot \left(4 \cdot \color{blue}{\frac{1}{\pi}}\right) \]
  8. Applied egg-rr96.0%

    \[\leadsto -\color{blue}{\log \left(\frac{4}{\pi \cdot f}\right) \cdot \left(4 \cdot \frac{1}{\pi}\right)} \]
  9. Step-by-step derivation
    1. *-commutative96.0%

      \[\leadsto -\color{blue}{\left(4 \cdot \frac{1}{\pi}\right) \cdot \log \left(\frac{4}{\pi \cdot f}\right)} \]
    2. associate-*r/96.0%

      \[\leadsto -\color{blue}{\frac{4 \cdot 1}{\pi}} \cdot \log \left(\frac{4}{\pi \cdot f}\right) \]
    3. metadata-eval96.0%

      \[\leadsto -\frac{\color{blue}{4}}{\pi} \cdot \log \left(\frac{4}{\pi \cdot f}\right) \]
    4. *-commutative96.0%

      \[\leadsto -\frac{4}{\pi} \cdot \log \left(\frac{4}{\color{blue}{f \cdot \pi}}\right) \]
  10. Simplified96.0%

    \[\leadsto -\color{blue}{\frac{4}{\pi} \cdot \log \left(\frac{4}{f \cdot \pi}\right)} \]
  11. Final simplification96.0%

    \[\leadsto \log \left(\frac{4}{\pi \cdot f}\right) \cdot \frac{-4}{\pi} \]

Alternative 8?

\[\frac{-\log \left(\frac{4}{\pi \cdot f}\right)}{\pi \cdot 0.25} \]
Derivation
  1. Initial program 7.9%

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right) \]
  2. Step-by-step derivation
    1. expm1-log1p-u7.9%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)\right)} \]
    2. expm1-udef7.9%

      \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\right)} - 1\right)} \]
  3. Applied egg-rr96.1%

    \[\leadsto -\color{blue}{\left(e^{\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)} - 1\right)} \]
  4. Step-by-step derivation
    1. expm1-def96.1%

      \[\leadsto -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}\right)\right)} \]
    2. expm1-log1p97.4%

      \[\leadsto -\color{blue}{\frac{\log \left(\frac{2 \cdot \cosh \left(\frac{\pi \cdot f}{4}\right)}{2 \cdot \sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25}} \]
    3. times-frac97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{2}{2} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    4. metadata-eval97.4%

      \[\leadsto -\frac{\log \left(\color{blue}{1} \cdot \frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    5. *-lft-identity97.4%

      \[\leadsto -\frac{\log \color{blue}{\left(\frac{\cosh \left(\frac{\pi \cdot f}{4}\right)}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}}{\pi \cdot 0.25} \]
    6. associate-/l*97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    7. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}{\sinh \left(\frac{\pi \cdot f}{4}\right)}\right)}{\pi \cdot 0.25} \]
    8. associate-/l*97.1%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{\frac{4}{f}}\right)}}\right)}{\pi \cdot 0.25} \]
    9. associate-/r/97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \color{blue}{\left(\frac{\pi}{4} \cdot f\right)}}\right)}{\pi \cdot 0.25} \]
    10. *-commutative97.4%

      \[\leadsto -\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{\color{blue}{0.25 \cdot \pi}} \]
  5. Simplified97.4%

    \[\leadsto -\color{blue}{\frac{\log \left(\frac{\cosh \left(\frac{\pi}{4} \cdot f\right)}{\sinh \left(\frac{\pi}{4} \cdot f\right)}\right)}{0.25 \cdot \pi}} \]
  6. Taylor expanded in f around 0 96.1%

    \[\leadsto -\frac{\log \color{blue}{\left(\frac{4}{f \cdot \pi}\right)}}{0.25 \cdot \pi} \]
  7. Final simplification96.1%

    \[\leadsto \frac{-\log \left(\frac{4}{\pi \cdot f}\right)}{\pi \cdot 0.25} \]

Reproduce

?
herbie shell --seed 2023166 
(FPCore (f)
  :name "VandenBroeck and Keller, Equation (20)"
  :precision binary64
  (- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ (exp (* (/ PI 4.0) f)) (exp (- (* (/ PI 4.0) f)))) (- (exp (* (/ PI 4.0) f)) (exp (- (* (/ PI 4.0) f)))))))))