\[\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\]

\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}

double f(double x) {
        double r7974 = 2.0;
        double r7975 = x;
        double r7976 = r7974 * r7975;
        double r7977 = exp(r7976);
        double r7978 = 1.0;
        double r7979 = r7977 - r7978;
        double r7980 = exp(r7975);
        double r7981 = r7980 - r7978;
        double r7982 = r7979 / r7981;
        double r7983 = sqrt(r7982);
        return r7983;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(FPCore (x)
  :name "sqrtexp (problem 3.4.4)"
  (sqrt (/ (- (exp (* 2.0 x)) 1.0) (- (exp x) 1.0))))

Backtrace

get-representation: Unknown representation #f		L	C
loop	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	122	4
prepare-points	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	146	0
setup-prog!34	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	67	0
run-improve43	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	339	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28