\[3 \cdot \left(\left(\left(x \cdot 3\right) \cdot x - x \cdot 4\right) + 1\right)\]
3 \cdot \left(\left(\left(x \cdot 3\right) \cdot x - x \cdot 4\right) + 1\right)
double f(double x) {
        double r9611 = 3.0;
        double r9612 = x;
        double r9613 = r9612 * r9611;
        double r9614 = r9613 * r9612;
        double r9615 = 4.0;
        double r9616 = r9612 * r9615;
        double r9617 = r9614 - r9616;
        double r9618 = 1.0;
        double r9619 = r9617 + r9618;
        double r9620 = r9611 * r9619;
        return r9620;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(FPCore (x)
  :name "Diagrams.Tangent:$catParam from diagrams-lib-1.3.0.3, D"

  :herbie-target
  (+ 3.0 (- (* (* 9.0 x) x) (* 12.0 x)))

  (* 3.0 (+ (- (* (* x 3.0) x) (* x 4.0)) 1.0)))

Backtrace

get-representation: Unknown representation #fLC
loop/data/pavpan/nightlies/herbie/interface2/src/points.rkt1224
prepare-points/data/pavpan/nightlies/herbie/interface2/src/points.rkt1460
setup-prog!34/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt670
run-improve43/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt3390
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128
run/opt/racket-7.0/share/pkgs/profile-lib/main.rkt392
profile-thunk16/opt/racket-7.0/share/pkgs/profile-lib/main.rkt90
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128