\[\frac{2}{\left(\left(\frac{{t}^{3}}{\ell \cdot \ell} \cdot \sin k\right) \cdot \tan k\right) \cdot \left(\left(1 + {\left(\frac{k}{t}\right)}^{2}\right) + 1\right)}\]

\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 r1379328 = 2.0;
        double r1379329 = t;
        double r1379330 = 3.0;
        double r1379331 = pow(r1379329, r1379330);
        double r1379332 = l;
        double r1379333 = r1379332 * r1379332;
        double r1379334 = r1379331 / r1379333;
        double r1379335 = k;
        double r1379336 = sin(r1379335);
        double r1379337 = r1379334 * r1379336;
        double r1379338 = tan(r1379335);
        double r1379339 = r1379337 * r1379338;
        double r1379340 = 1.0;
        double r1379341 = r1379335 / r1379329;
        double r1379342 = pow(r1379341, r1379328);
        double r1379343 = r1379340 + r1379342;
        double r1379344 = r1379343 + r1379340;
        double r1379345 = r1379339 * r1379344;
        double r1379346 = r1379328 / r1379345;
        return r1379346;
}

Reproduce

herbie shell --seed 2019142 
(FPCore (t l k)
  :name "Toniolo and Linder, Equation (10+)"
  (/ 2 (* (* (* (/ (pow t 3) (* l l)) (sin k)) (tan k)) (+ (+ 1 (pow (/ k t) 2)) 1))))

Timeout in 10.0m

Reproduce