El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$- \sin{\left(2 x \right)} + 4 \cos{\left(2 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \frac{\operatorname{atan}{\left(4 \right)}}{2}$$
Solución numérica$$x_{1} = 52.4991876160656$$
$$x_{2} = 47.7867986356809$$
$$x_{3} = -324.49193081471$$
$$x_{4} = -4.04948014855067$$
$$x_{5} = -57.4565552595772$$
$$x_{6} = 54.0699839428605$$
$$x_{7} = 85.4859104787584$$
$$x_{8} = 30.5080390409371$$
$$x_{9} = -21.3282397432945$$
$$x_{10} = -43.3193883184231$$
$$x_{11} = -79.4477038347057$$
$$x_{12} = -93.5848707758598$$
$$x_{13} = 3.80450148542381$$
$$x_{14} = 22.6540574069626$$
$$x_{15} = -99.8680560830394$$
$$x_{16} = 19.5124647533728$$
$$x_{17} = -35.4654066844486$$
$$x_{18} = 96.4814847663227$$
$$x_{19} = -24.4698323968843$$
$$x_{20} = 83.9151141519635$$
$$x_{21} = 44.6452059820911$$
$$x_{22} = -33.8946103576537$$
$$x_{23} = -19.7574434164996$$
$$x_{24} = 88.6275031323482$$
$$x_{25} = 11.6584831193983$$
$$x_{26} = 74.4903361911942$$
$$x_{27} = -62.1689442399618$$
$$x_{28} = -32.3238140308588$$
$$x_{29} = -49.6025736256027$$
$$x_{30} = -41.7485919916282$$
$$x_{31} = 68.2071508840146$$
$$x_{32} = 0.662908831834016$$
$$x_{33} = -1537.14669510037$$
$$x_{34} = 77.631928844784$$
$$x_{35} = -18.1866470897047$$
$$x_{36} = -98.2972597562445$$
$$x_{37} = -63.7397405667567$$
$$x_{38} = -48.0317772988078$$
$$x_{39} = -70.0229258739363$$
$$x_{40} = 98.0522810931176$$
$$x_{41} = -71.5937222007312$$
$$x_{42} = 69.7779472108095$$
$$x_{43} = -13.4742581093201$$
$$x_{44} = -55.8857589327823$$
$$x_{45} = 55.6407802696554$$
$$x_{46} = 8.5168904658085$$
$$x_{47} = 46.216002308886$$
$$x_{48} = 76.0611325179891$$
$$x_{49} = -11.9034617825252$$
$$x_{50} = -92.0140744490649$$
$$x_{51} = -77.8769075079108$$
$$x_{52} = 10.0876867926034$$
$$x_{53} = 25.7956500605524$$
$$x_{54} = 16.370872099783$$
$$x_{55} = 66.6363545572197$$
$$x_{56} = 60.3531692500401$$
$$x_{57} = -76.3061111811159$$
$$x_{58} = -26.0406287236792$$
$$x_{59} = -46.4609809720129$$
$$x_{60} = 63.4947619036299$$
$$x_{61} = 153.030152530939$$
$$x_{62} = 38.3620206749115$$
$$x_{63} = -5.62027647534557$$
$$x_{64} = 2.23370515862891$$
$$x_{65} = -84.1600928150904$$
$$x_{66} = 82.3443178251686$$
$$x_{67} = -10.3326654557303$$
$$x_{68} = 90.1982994591431$$
$$x_{69} = -54.3149626059874$$
$$x_{70} = 41.5036133285013$$
$$x_{71} = -65.3105368935516$$
$$x_{72} = 17.9416684265779$$
$$x_{73} = 33.6496316945268$$
$$x_{74} = 91.769095785938$$
$$x_{75} = -85.7308891418853$$
$$x_{76} = 79.2027251715788$$
$$x_{77} = -40.1777956648333$$
$$x_{78} = -90.44327812227$$
$$x_{79} = 24.2248537337575$$
$$x_{80} = -87.3016854686802$$
$$x_{81} = 99.6230774199125$$
$$x_{82} = -27.6114250504741$$
$$x_{83} = 61.923965576835$$
$$x_{84} = -68.4521295471414$$
$$x_{85} = -2.47868382175578$$
$$x_{86} = 39.9328170017064$$
$$x_{87} = 32.0788353677319$$