Average Error: 4.6 → 0.9
Time: 24.5s
Precision: 64
\[\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\]
\[\begin{array}{l} \mathbf{if}\;x \le -1.288683916673524238328662344654773619368 \cdot 10^{-5}:\\ \;\;\;\;\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x + x} - 1 \cdot 1}} \cdot \sqrt{e^{x} + 1}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2 + x \cdot \left(0.5 \cdot x + 1\right)}\\ \end{array}\]
\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}
\begin{array}{l}
\mathbf{if}\;x \le -1.288683916673524238328662344654773619368 \cdot 10^{-5}:\\
\;\;\;\;\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x + x} - 1 \cdot 1}} \cdot \sqrt{e^{x} + 1}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{2 + x \cdot \left(0.5 \cdot x + 1\right)}\\

\end{array}
double f(double x) {
        double r18852 = 2.0;
        double r18853 = x;
        double r18854 = r18852 * r18853;
        double r18855 = exp(r18854);
        double r18856 = 1.0;
        double r18857 = r18855 - r18856;
        double r18858 = exp(r18853);
        double r18859 = r18858 - r18856;
        double r18860 = r18857 / r18859;
        double r18861 = sqrt(r18860);
        return r18861;
}

double f(double x) {
        double r18862 = x;
        double r18863 = -1.2886839166735242e-05;
        bool r18864 = r18862 <= r18863;
        double r18865 = 2.0;
        double r18866 = r18865 * r18862;
        double r18867 = exp(r18866);
        double r18868 = 1.0;
        double r18869 = r18867 - r18868;
        double r18870 = r18862 + r18862;
        double r18871 = exp(r18870);
        double r18872 = r18868 * r18868;
        double r18873 = r18871 - r18872;
        double r18874 = r18869 / r18873;
        double r18875 = sqrt(r18874);
        double r18876 = exp(r18862);
        double r18877 = r18876 + r18868;
        double r18878 = sqrt(r18877);
        double r18879 = r18875 * r18878;
        double r18880 = 0.5;
        double r18881 = r18880 * r18862;
        double r18882 = r18881 + r18868;
        double r18883 = r18862 * r18882;
        double r18884 = r18865 + r18883;
        double r18885 = sqrt(r18884);
        double r18886 = r18864 ? r18879 : r18885;
        return r18886;
}

Error

Bits error versus x

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Split input into 2 regimes
  2. if x < -1.2886839166735242e-05

    1. Initial program 0.1

      \[\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\]
    2. Using strategy rm
    3. Applied flip--0.1

      \[\leadsto \sqrt{\frac{e^{2 \cdot x} - 1}{\color{blue}{\frac{e^{x} \cdot e^{x} - 1 \cdot 1}{e^{x} + 1}}}}\]
    4. Applied associate-/r/0.1

      \[\leadsto \sqrt{\color{blue}{\frac{e^{2 \cdot x} - 1}{e^{x} \cdot e^{x} - 1 \cdot 1} \cdot \left(e^{x} + 1\right)}}\]
    5. Applied sqrt-prod0.1

      \[\leadsto \color{blue}{\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} \cdot e^{x} - 1 \cdot 1}} \cdot \sqrt{e^{x} + 1}}\]
    6. Simplified0.0

      \[\leadsto \color{blue}{\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x + x} - 1 \cdot 1}}} \cdot \sqrt{e^{x} + 1}\]

    if -1.2886839166735242e-05 < x

    1. Initial program 33.9

      \[\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\]
    2. Taylor expanded around 0 6.5

      \[\leadsto \sqrt{\color{blue}{0.5 \cdot {x}^{2} + \left(1 \cdot x + 2\right)}}\]
    3. Simplified6.5

      \[\leadsto \sqrt{\color{blue}{2 + x \cdot \left(0.5 \cdot x + 1\right)}}\]
  3. Recombined 2 regimes into one program.
  4. Final simplification0.9

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \le -1.288683916673524238328662344654773619368 \cdot 10^{-5}:\\ \;\;\;\;\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x + x} - 1 \cdot 1}} \cdot \sqrt{e^{x} + 1}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{2 + x \cdot \left(0.5 \cdot x + 1\right)}\\ \end{array}\]

Reproduce

herbie shell --seed 2019306 
(FPCore (x)
  :name "sqrtexp (problem 3.4.4)"
  :precision binary64
  (sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))