El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cos{\left(2 x \right)} + \tan{\left(x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \operatorname{atan}{\left(- \frac{\sqrt[3]{17 + 3 \sqrt{33}}}{3} + \frac{2}{3 \sqrt[3]{17 + 3 \sqrt{33}}} + \frac{1}{3} \right)}$$
Solución numérica$$x_{1} = 81.1834239786949$$
$$x_{2} = 52.9090900963868$$
$$x_{3} = 5.78520029253992$$
$$x_{4} = 68.6170533643358$$
$$x_{5} = -123.020098504642$$
$$x_{6} = 27.7763488676685$$
$$x_{7} = 12.0683855997195$$
$$x_{8} = 56.0506827499766$$
$$x_{9} = -60.1882454328457$$
$$x_{10} = 18.3515709068991$$
$$x_{11} = -69.6130233936151$$
$$x_{12} = -91.6041719687437$$
$$x_{13} = 24.6347562140787$$
$$x_{14} = -66.4714307400253$$
$$x_{15} = 90.6082019394643$$
$$x_{16} = -38.1970968577172$$
$$x_{17} = -13.0643556289988$$
$$x_{18} = 231.979871351005$$
$$x_{19} = -16.2059482825886$$
$$x_{20} = 71.7586460179256$$
$$x_{21} = 93.7497945930541$$
$$x_{22} = -113.595320543872$$
$$x_{23} = 15.2099782533093$$
$$x_{24} = 34.0595341748481$$
$$x_{25} = 30.9179415212583$$
$$x_{26} = 78.0418313251052$$
$$x_{27} = -35.0555042041274$$
$$x_{28} = -88.4625793151539$$
$$x_{29} = 103.174572553824$$
$$x_{30} = -6.78117032181926$$
$$x_{31} = -25.630726243358$$
$$x_{32} = -47.6218748184866$$
$$x_{33} = -82.1793940079743$$
$$x_{34} = -9.92276297540905$$
$$x_{35} = 21.4931635604889$$
$$x_{36} = -53.9050601256662$$
$$x_{37} = -79.0378013543845$$
$$x_{38} = 46.6259047892072$$
$$x_{39} = 37.2011268284379$$
$$x_{40} = 59.1922754035664$$
$$x_{41} = 7297.42174927445$$
$$x_{42} = -85.3209866615641$$
$$x_{43} = 96.8913872466439$$
$$x_{44} = 2.64360763895012$$
$$x_{45} = -57.046652779256$$
$$x_{46} = -63.3298380864355$$
$$x_{47} = 8.92679294612971$$
$$x_{48} = 40.3427194820276$$
$$x_{49} = 74.9002386715154$$
$$x_{50} = 62.3338680571562$$
$$x_{51} = -97.8873572759233$$
$$x_{52} = 49.767497442797$$
$$x_{53} = 100.032979900234$$
$$x_{54} = -31.9139115505376$$
$$x_{55} = -19.3475409361784$$
$$x_{56} = -138.728061772591$$
$$x_{57} = -75.8962087007947$$
$$x_{58} = -22.4891335897682$$
$$x_{59} = -3.63957766822946$$
$$x_{60} = 84.3250166322847$$
$$x_{61} = -41.338689511307$$