El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\tan{\left(x \right)} - \frac{\cot{\left(x \right)}}{4} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \operatorname{atan}{\left(\frac{1}{2} \right)}$$
$$x_{2} = \operatorname{atan}{\left(\frac{1}{2} \right)}$$
Solución numérica$$x_{1} = 56.0850201556155$$
$$x_{2} = 16.1716108769498$$
$$x_{3} = -3.6052402625906$$
$$x_{4} = -2.67794504458899$$
$$x_{5} = -18.385908312538$$
$$x_{6} = 59.2266128092053$$
$$x_{7} = -53.8707227200273$$
$$x_{8} = -71.7929834235644$$
$$x_{9} = -65.5097981163849$$
$$x_{10} = -90.6425393451032$$
$$x_{11} = -40.3770568876665$$
$$x_{12} = 85.2866492559252$$
$$x_{13} = 18.385908312538$$
$$x_{14} = 5.81953769817878$$
$$x_{15} = -57.0123153736171$$
$$x_{16} = -63.2955006807967$$
$$x_{17} = 60.1539080272069$$
$$x_{18} = -84.3593540379236$$
$$x_{19} = -31.8795741448987$$
$$x_{20} = -82.1450566023354$$
$$x_{21} = -16.1716108769498$$
$$x_{22} = 37.2354642340767$$
$$x_{23} = 96.9257246522828$$
$$x_{24} = 2.67794504458899$$
$$x_{25} = 68.6513907699746$$
$$x_{26} = 71.7929834235644$$
$$x_{27} = 9.88842556977019$$
$$x_{28} = 27.8106862733073$$
$$x_{29} = -79.0034639487456$$
$$x_{30} = 24.6690936197175$$
$$x_{31} = -24.6690936197175$$
$$x_{32} = 53.8707227200273$$
$$x_{33} = -9.88842556977019$$
$$x_{34} = 12.1027230053584$$
$$x_{35} = 88.428241909515$$
$$x_{36} = -49.8018348484359$$
$$x_{37} = -87.5009466915134$$
$$x_{38} = 63.2955006807967$$
$$x_{39} = 47.5875374128477$$
$$x_{40} = -25.5963888377192$$
$$x_{41} = -74.9345760771542$$
$$x_{42} = 15.2443156589482$$
$$x_{43} = -47.5875374128477$$
$$x_{44} = 97.8530198702844$$
$$x_{45} = -85.2866492559252$$
$$x_{46} = 25.5963888377192$$
$$x_{47} = 74.9345760771542$$
$$x_{48} = -78.076168730744$$
$$x_{49} = -21.5275009661277$$
$$x_{50} = 40.3770568876665$$
$$x_{51} = -100.067317305873$$
$$x_{52} = -69.5786859879763$$
$$x_{53} = -35.0211667984885$$
$$x_{54} = 69.5786859879763$$
$$x_{55} = 31.8795741448987$$
$$x_{56} = -46.6602421948461$$
$$x_{57} = 82.1450566023354$$
$$x_{58} = 52.9434275020257$$
$$x_{59} = 66.4370933343865$$
$$x_{60} = -52.9434275020257$$
$$x_{61} = -60.1539080272069$$
$$x_{62} = -91.5698345631048$$
$$x_{63} = -30.9522789268971$$
$$x_{64} = 49.8018348484359$$
$$x_{65} = 41.3043521056681$$
$$x_{66} = -43.5186495412563$$
$$x_{67} = 100.067317305873$$
$$x_{68} = -38.1627594520783$$
$$x_{69} = 34.0938715804869$$
$$x_{70} = -96.9257246522828$$
$$x_{71} = -19.3132035305396$$
$$x_{72} = 44.4459447592579$$
$$x_{73} = -13.03001822336$$
$$x_{74} = 38.1627594520783$$
$$x_{75} = 81.2177613843338$$
$$x_{76} = 90.6425393451032$$
$$x_{77} = -41.3043521056681$$
$$x_{78} = -6.74683291618039$$
$$x_{79} = 30.9522789268971$$
$$x_{80} = 46.6602421948461$$
$$x_{81} = 78.076168730744$$
$$x_{82} = -93.784131998693$$
$$x_{83} = -12.1027230053584$$
$$x_{84} = 91.5698345631048$$
$$x_{85} = 8.96113035176857$$
$$x_{86} = -56.0850201556155$$
$$x_{87} = 75.8618712951559$$
$$x_{88} = 19.3132035305396$$
$$x_{89} = -97.8530198702844$$
$$x_{90} = 93.784131998693$$
$$x_{91} = 62.3682054627951$$
$$x_{92} = -68.6513907699746$$
$$x_{93} = -75.8618712951559$$
$$x_{94} = 22.4547961841294$$
$$x_{95} = -34.0938715804869$$
$$x_{96} = -5.81953769817878$$
$$x_{97} = -27.8106862733073$$
$$x_{98} = 3.6052402625906$$
$$x_{99} = -62.3682054627951$$
$$x_{100} = 84.3593540379236$$