\[\frac{2}{\left(\left(\frac{{t}^{3}}{\ell \cdot \ell} \cdot \sin k\right) \cdot \tan k\right) \cdot \left(\left(1 + {\left(\frac{k}{t}\right)}^{2}\right) + 1\right)}\]
\frac{2}{\left(\left(\frac{{t}^{3}}{\ell \cdot \ell} \cdot \sin k\right) \cdot \tan k\right) \cdot \left(\left(1 + {\left(\frac{k}{t}\right)}^{2}\right) + 1\right)}
double f(double t, double l, double k) {
        double r8156 = 2.0;
        double r8157 = t;
        double r8158 = 3.0;
        double r8159 = pow(r8157, r8158);
        double r8160 = l;
        double r8161 = r8160 * r8160;
        double r8162 = r8159 / r8161;
        double r8163 = k;
        double r8164 = sin(r8163);
        double r8165 = r8162 * r8164;
        double r8166 = tan(r8163);
        double r8167 = r8165 * r8166;
        double r8168 = 1.0;
        double r8169 = r8163 / r8157;
        double r8170 = pow(r8169, r8156);
        double r8171 = r8168 + r8170;
        double r8172 = r8171 + r8168;
        double r8173 = r8167 * r8172;
        double r8174 = r8156 / r8173;
        return r8174;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019179 
(FPCore (t l k)
  :name "Toniolo and Linder, Equation (10+)"
  (/ 2.0 (* (* (* (/ (pow t 3.0) (* l l)) (sin k)) (tan k)) (+ (+ 1.0 (pow (/ k t) 2.0)) 1.0))))

Backtrace

result arity mismatch; expected number of values not received expected: 2 received: 1 in: local-binding form values...: 0LC
loop/data/pavpan/nightlies/herbie/various-cleanup/src/core/extraction.rkt252
(unnamed)/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt260
simplify!/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt2170
run-improve43/data/pavpan/nightlies/herbie/various-cleanup/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