El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cot^{2}{\left(3 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \frac{\pi}{6}$$
Solución numérica$$x_{1} = -36.1283153645083$$
$$x_{2} = 100.007366130115$$
$$x_{3} = -53.9306741145521$$
$$x_{4} = 29.8451304069767$$
$$x_{5} = 51.8362789998718$$
$$x_{6} = 38.2227107552624$$
$$x_{7} = 82.2050078071905$$
$$x_{8} = 56.0250689540478$$
$$x_{9} = -82.2050074484677$$
$$x_{10} = -25.6563400744707$$
$$x_{11} = 20.4203520960862$$
$$x_{12} = -91.6297858239975$$
$$x_{13} = -14.1371667750801$$
$$x_{14} = 66.497044201419$$
$$x_{15} = -67.5442422606536$$
$$x_{16} = -78.0162175456938$$
$$x_{17} = 97.9129711323516$$
$$x_{18} = 16.2315620577815$$
$$x_{19} = -51.8362786802551$$
$$x_{20} = 88.4881927989617$$
$$x_{21} = 60.2138592233635$$
$$x_{22} = 9.94837679221298$$
$$x_{23} = 64.4026492691327$$
$$x_{24} = 18.3259570902494$$
$$x_{25} = 86.3937978546149$$
$$x_{26} = 75.9218225468$$
$$x_{27} = -29.8451300757966$$
$$x_{28} = -95.8185758665662$$
$$x_{29} = -100.007366130666$$
$$x_{30} = -34.0339203766245$$
$$x_{31} = 7.85398181537257$$
$$x_{32} = -3.66519149197579$$
$$x_{33} = -41.3643032131145$$
$$x_{34} = 42.4115006829809$$
$$x_{35} = -69.6386372404368$$
$$x_{36} = 31.9395253768109$$
$$x_{37} = 22.5147470008466$$
$$x_{38} = 14.1371671771581$$
$$x_{39} = 44.5058956020754$$
$$x_{40} = -56.0250689610676$$
$$x_{41} = -27.7507351061632$$
$$x_{42} = -9.94837683648$$
$$x_{43} = -19.3731549194184$$
$$x_{44} = 78.0162175429281$$
$$x_{45} = 40.3171056722448$$
$$x_{46} = -58.1194639530272$$
$$x_{47} = -93.7241808507675$$
$$x_{48} = -87.4409954320782$$
$$x_{49} = 95.8185761901643$$
$$x_{50} = -12.0427717922339$$
$$x_{51} = -73.8274272758422$$
$$x_{52} = 53.9306739616462$$
$$x_{53} = -47.6474886572765$$
$$x_{54} = 80.1106129896839$$
$$x_{55} = -80.1106125407425$$
$$x_{56} = -5.75958652433335$$
$$x_{57} = -49.7418836877985$$
$$x_{58} = 12.0427717667947$$
$$x_{59} = 91.6297860963422$$
$$x_{60} = -45.5530936699011$$
$$x_{61} = -89.5353908526334$$
$$x_{62} = 84.2994028357026$$
$$x_{63} = -7.85398145280268$$
$$x_{64} = -60.2138588449473$$
$$x_{65} = -1.57079649163217$$
$$x_{66} = -23.5619450802624$$
$$x_{67} = 62.3082542540495$$
$$x_{68} = 73.8274275942116$$
$$x_{69} = -71.7330322693127$$
$$x_{70} = -31.9395254550888$$
$$x_{71} = 38.2227106402965$$
$$x_{72} = 34.0339203625488$$