El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\frac{\left(-1\right) 2 x}{\left(x^{2} - 1\right)^{2}} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
Solución numérica$$x_{1} = -24509.4076256731$$
$$x_{2} = -27900.492652453$$
$$x_{3} = 22945.0573071609$$
$$x_{4} = -37225.3490351873$$
$$x_{5} = 23792.8707458989$$
$$x_{6} = 0$$
$$x_{7} = 39899.6373793217$$
$$x_{8} = 18705.7058128052$$
$$x_{9} = -27052.737092296$$
$$x_{10} = 26336.230277608$$
$$x_{11} = 30574.9607286225$$
$$x_{12} = -36377.6604419003$$
$$x_{13} = -23661.6064602865$$
$$x_{14} = 13617.3916429577$$
$$x_{15} = -22813.7906651013$$
$$x_{16} = -25357.1956280906$$
$$x_{17} = -26204.9717446159$$
$$x_{18} = 16161.7601634659$$
$$x_{19} = 33118.1118739225$$
$$x_{20} = -13486.0629303382$$
$$x_{21} = -33834.5693054934$$
$$x_{22} = 29727.2308152591$$
$$x_{23} = -39768.3932412975$$
$$x_{24} = -28748.239290691$$
$$x_{25} = 12769.1311938499$$
$$x_{26} = -34682.2708868702$$
$$x_{27} = -29595.9777734643$$
$$x_{28} = -11789.4194932989$$
$$x_{29} = 39051.9598251782$$
$$x_{30} = 32270.4007511367$$
$$x_{31} = 21249.3803723555$$
$$x_{32} = -32139.1507408333$$
$$x_{33} = -38073.0338727658$$
$$x_{34} = -17726.4711883433$$
$$x_{35} = -31291.43292325$$
$$x_{36} = -21118.1081408212$$
$$x_{37} = 19553.622232257$$
$$x_{38} = -16878.4853984547$$
$$x_{39} = 22097.2278225587$$
$$x_{40} = -19422.3428903681$$
$$x_{41} = 36508.9067380414$$
$$x_{42} = 34813.5185064768$$
$$x_{43} = 25488.4558880833$$
$$x_{44} = 33965.8176625065$$
$$x_{45} = 20401.5127178497$$
$$x_{46} = -15182.3860741083$$
$$x_{47} = -38920.7151999899$$
$$x_{48} = -30443.7087818787$$
$$x_{49} = 31422.6838625292$$
$$x_{50} = -35529.96782414$$
$$x_{51} = -12637.7892988554$$
$$x_{52} = 41594.9835238138$$
$$x_{53} = 17857.7597678008$$
$$x_{54} = -16030.4592776001$$
$$x_{55} = -14334.2574401388$$
$$x_{56} = 28031.748190538$$
$$x_{57} = 27183.9940576599$$
$$x_{58} = 40747.3118833833$$
$$x_{59} = 11920.7774961659$$
$$x_{60} = 28879.4935255786$$
$$x_{61} = 24640.6697943983$$
$$x_{62} = 42442.6524721704$$
$$x_{63} = -41463.7402721613$$
$$x_{64} = 35661.2147583842$$
$$x_{65} = -40616.0682023929$$
$$x_{66} = 14465.575228032$$
$$x_{67} = -21965.9585469319$$
$$x_{68} = 15313.6947073257$$
$$x_{69} = 37356.5947362375$$
$$x_{70} = -18574.4221668727$$
$$x_{71} = 17009.7796699387$$
$$x_{72} = -20270.2371532321$$
$$x_{73} = -32986.8627220526$$
$$x_{74} = -42311.4096243535$$
$$x_{75} = 38204.2790179564$$