El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\frac{x}{\cot{\left(x \right)}} - \frac{\pi}{2 \cos{\left(x \right)}} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución numérica$$x_{1} = -91.0889414557436$$
$$x_{2} = 84.8044780241535$$
$$x_{3} = 87.9824487681817$$
$$x_{4} = 25.195126931748$$
$$x_{5} = -40.8021971440169$$
$$x_{6} = 56.5764354772874$$
$$x_{7} = -56.5764354772874$$
$$x_{8} = 59.6639299728984$$
$$x_{9} = 21.9194247993218$$
$$x_{10} = 34.5119889486404$$
$$x_{11} = -47.090526665132$$
$$x_{12} = -25.195126931748$$
$$x_{13} = -50.296718129333$$
$$x_{14} = -18.9326191287497$$
$$x_{15} = 15.6071466065859$$
$$x_{16} = -44.0179900545107$$
$$x_{17} = 44.0179900545107$$
$$x_{18} = -69.1377601375797$$
$$x_{19} = -94.2644440992445$$
$$x_{20} = 6.52626052349572$$
$$x_{21} = 47.090526665132$$
$$x_{22} = -75.4190527718659$$
$$x_{23} = -81.700636421485$$
$$x_{24} = -100.546588122574$$
$$x_{25} = -87.9824487681817$$
$$x_{26} = 81.700636421485$$
$$x_{27} = -6.52626052349572$$
$$x_{28} = -53.3776428796593$$
$$x_{29} = 69.1377601375797$$
$$x_{30} = -97.3732398570868$$
$$x_{31} = -28.2186398913309$$
$$x_{32} = 97.3732398570868$$
$$x_{33} = -31.4658679354259$$
$$x_{34} = 2.44332268625344$$
$$x_{35} = 62.8568457332786$$
$$x_{36} = -65.9496253492124$$
$$x_{37} = 75.4190527718659$$
$$x_{38} = 40.8021971440169$$
$$x_{39} = -34.5119889486404$$
$$x_{40} = 94.2644440992445$$
$$x_{41} = 50.296718129333$$
$$x_{42} = 9.25421365001762$$
$$x_{43} = 100.546588122574$$
$$x_{44} = -62.8568457332786$$
$$x_{45} = -15.6071466065859$$
$$x_{46} = 18.9326191287497$$
$$x_{47} = 37.7407445720846$$
$$x_{48} = 12.6904665437507$$
$$x_{49} = -72.2348836430472$$
$$x_{50} = -12.6904665437507$$
$$x_{51} = -9.25421365001762$$
$$x_{52} = -21.9194247993218$$
$$x_{53} = 31.4658679354259$$
$$x_{54} = -78.5198099092579$$
$$x_{55} = 78.5198099092579$$
$$x_{56} = 91.0889414557436$$
$$x_{57} = -37.7407445720846$$
$$x_{58} = -2.44332268625344$$
$$x_{59} = 72.2348836430472$$
$$x_{60} = 28.2186398913309$$
$$x_{61} = -84.8044780241535$$
$$x_{62} = 53.3776428796593$$
$$x_{63} = 65.9496253492124$$
$$x_{64} = -59.6639299728984$$