\[\alpha \gt -1 \land \beta \gt -1 \land i \gt 1\]

\[\frac{\frac{\left(i \cdot \left(\left(\alpha + \beta\right) + i\right)\right) \cdot \left(\beta \cdot \alpha + i \cdot \left(\left(\alpha + \beta\right) + i\right)\right)}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) \cdot \left(\left(\alpha + \beta\right) + 2 \cdot i\right)}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) \cdot \left(\left(\alpha + \beta\right) + 2 \cdot i\right) - 1}\]

\frac{\frac{\left(i \cdot \left(\left(\alpha + \beta\right) + i\right)\right) \cdot \left(\beta \cdot \alpha + i \cdot \left(\left(\alpha + \beta\right) + i\right)\right)}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) \cdot \left(\left(\alpha + \beta\right) + 2 \cdot i\right)}}{\left(\left(\alpha + \beta\right) + 2 \cdot i\right) \cdot \left(\left(\alpha + \beta\right) + 2 \cdot i\right) - 1}

double f(double alpha, double beta, double i) {
        double r949625 = i;
        double r949626 = alpha;
        double r949627 = beta;
        double r949628 = r949626 + r949627;
        double r949629 = r949628 + r949625;
        double r949630 = r949625 * r949629;
        double r949631 = r949627 * r949626;
        double r949632 = r949631 + r949630;
        double r949633 = r949630 * r949632;
        double r949634 = 2.0;
        double r949635 = r949634 * r949625;
        double r949636 = r949628 + r949635;
        double r949637 = r949636 * r949636;
        double r949638 = r949633 / r949637;
        double r949639 = 1.0;
        double r949640 = r949637 - r949639;
        double r949641 = r949638 / r949640;
        return r949641;
}

Reproduce

herbie shell --seed 2019350 +o rules:numerics
(FPCore (alpha beta i)
  :name "Octave 3.8, jcobi/4"
  :precision binary64
  :pre (and (> alpha -1) (> beta -1) (> i 1))
  (/ (/ (* (* i (+ (+ alpha beta) i)) (+ (* beta alpha) (* i (+ (+ alpha beta) i)))) (* (+ (+ alpha beta) (* 2 i)) (+ (+ alpha beta) (* 2 i)))) (- (* (+ (+ alpha beta) (* 2 i)) (+ (+ alpha beta) (* 2 i))) 1)))

Timeout in 10.0m

Reproduce