Graph of the function intersects the axis X at f = 0
so we need to solve the equation:
$$2 \sin{\left(x \right)} - \cos{\left(x \right)} = 0$$
Solve this equationThe points of intersection with the axis X:
Analytical solution$$x_{1} = \operatorname{atan}{\left(\frac{1}{2} \right)}$$
Numerical solution$$x_{1} = -37.2354642340767$$
$$x_{2} = 63.2955006807967$$
$$x_{3} = 3.6052402625906$$
$$x_{4} = 47.5875374128477$$
$$x_{5} = -5.81953769817878$$
$$x_{6} = -34.0938715804869$$
$$x_{7} = -62.3682054627951$$
$$x_{8} = 35.0211667984885$$
$$x_{9} = -46.6602421948461$$
$$x_{10} = -96.9257246522828$$
$$x_{11} = -52.9434275020257$$
$$x_{12} = -68.6513907699746$$
$$x_{13} = 97.8530198702844$$
$$x_{14} = -93.784131998693$$
$$x_{15} = 4785.10925902626$$
$$x_{16} = 13.03001822336$$
$$x_{17} = -1271.88137709487$$
$$x_{18} = 19.3132035305396$$
$$x_{19} = -24.6690936197175$$
$$x_{20} = 16.1716108769498$$
$$x_{21} = 368.029988079007$$
$$x_{22} = -87.5009466915134$$
$$x_{23} = 75.8618712951559$$
$$x_{24} = -8.96113035176857$$
$$x_{25} = -238.297394063823$$
$$x_{26} = -74.9345760771542$$
$$x_{27} = 60.1539080272069$$
$$x_{28} = -12.1027230053584$$
$$x_{29} = 69.5786859879763$$
$$x_{30} = -21.5275009661277$$
$$x_{31} = -15.2443156589482$$
$$x_{32} = 85.2866492559252$$
$$x_{33} = -30.9522789268971$$
$$x_{34} = 91.5698345631048$$
$$x_{35} = -81.2177613843338$$
$$x_{36} = -100.067317305873$$
$$x_{37} = -49.8018348484359$$
$$x_{38} = -18.385908312538$$
$$x_{39} = 22.4547961841294$$
$$x_{40} = -2.67794504458899$$
$$x_{41} = -90.6425393451032$$
$$x_{42} = -71.7929834235644$$
$$x_{43} = 72.7202786415661$$
$$x_{44} = 50.7291300664375$$
$$x_{45} = -27.8106862733073$$
$$x_{46} = 94.7114272166946$$
$$x_{47} = 44.4459447592579$$
$$x_{48} = -43.5186495412563$$
$$x_{49} = 0.463647609000806$$
$$x_{50} = -78.076168730744$$
$$x_{51} = -59.2266128092053$$
$$x_{52} = 6.74683291618039$$
$$x_{53} = 41.3043521056681$$
$$x_{54} = 9.88842556977019$$
$$x_{55} = -56.0850201556155$$
$$x_{56} = 31.8795741448987$$
$$x_{57} = 100.994612523874$$
$$x_{58} = 66.4370933343865$$
$$x_{59} = -40.3770568876665$$
$$x_{60} = -65.5097981163849$$
$$x_{61} = 82.1450566023354$$
$$x_{62} = 57.0123153736171$$
$$x_{63} = -84.3593540379236$$
$$x_{64} = 53.8707227200273$$
$$x_{65} = 79.0034639487456$$
$$x_{66} = 38.1627594520783$$
$$x_{67} = 25.5963888377192$$
$$x_{68} = 28.7379814913089$$
$$x_{69} = 88.428241909515$$