El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sin{\left(x \right)} \cos{\left(2 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = - \frac{\pi}{4}$$
$$x_{3} = \frac{\pi}{4}$$
Solución numérica$$x_{1} = 69.1150383789755$$
$$x_{2} = -55.7632696012188$$
$$x_{3} = -98.174770424681$$
$$x_{4} = -11.7809724509617$$
$$x_{5} = 25.9181393921158$$
$$x_{6} = -40.0553063332699$$
$$x_{7} = 18.0641577581413$$
$$x_{8} = -13.3517687777566$$
$$x_{9} = 101.316363078271$$
$$x_{10} = 96.6039740978861$$
$$x_{11} = -41.6261026600648$$
$$x_{12} = 52.621676947629$$
$$x_{13} = 76.1836218495525$$
$$x_{14} = 69.9004365423729$$
$$x_{15} = 30.6305283725005$$
$$x_{16} = 85.6083998103219$$
$$x_{17} = -19.6349540849362$$
$$x_{18} = 28.2743338823081$$
$$x_{19} = -3.92699081698724$$
$$x_{20} = 50.2654824574367$$
$$x_{21} = 32.2013246992954$$
$$x_{22} = 84.037603483527$$
$$x_{23} = -91.8915851175014$$
$$x_{24} = 98.174770424681$$
$$x_{25} = -280.387144332889$$
$$x_{26} = -85.6083998103219$$
$$x_{27} = 41.6261026600648$$
$$x_{28} = 91.8915851175014$$
$$x_{29} = -2.35619449019234$$
$$x_{30} = 46.3384916404494$$
$$x_{31} = 65.9734457253857$$
$$x_{32} = 0$$
$$x_{33} = 63.6172512351933$$
$$x_{34} = 54.1924732744239$$
$$x_{35} = -43.1968989868597$$
$$x_{36} = 78.5398163397448$$
$$x_{37} = -84.037603483527$$
$$x_{38} = 100.530964914873$$
$$x_{39} = -72.2566310325652$$
$$x_{40} = 21.9911485751286$$
$$x_{41} = 47.9092879672443$$
$$x_{42} = 24.3473430653209$$
$$x_{43} = 68.329640215578$$
$$x_{44} = 62.0464549083984$$
$$x_{45} = -68.329640215578$$
$$x_{46} = -37.6991118430775$$
$$x_{47} = -81.6814089933346$$
$$x_{48} = 74.6128255227576$$
$$x_{49} = -51.0508806208341$$
$$x_{50} = -21.9911485751286$$
$$x_{51} = -87.9645943005142$$
$$x_{52} = -47.9092879672443$$
$$x_{53} = 40.0553063332699$$
$$x_{54} = -57.3340659280137$$
$$x_{55} = -43.9822971502571$$
$$x_{56} = -25.9181393921158$$
$$x_{57} = -76.1836218495525$$
$$x_{58} = -62.0464549083984$$
$$x_{59} = 60.4756585816035$$
$$x_{60} = -33.7721210260903$$
$$x_{61} = 94.2477796076938$$
$$x_{62} = -59.6902604182061$$
$$x_{63} = 87.9645943005142$$
$$x_{64} = -46.3384916404494$$
$$x_{65} = -63.6172512351933$$
$$x_{66} = -90.3207887907066$$
$$x_{67} = -35.3429173528852$$
$$x_{68} = 8.63937979737193$$
$$x_{69} = -15.707963267949$$
$$x_{70} = -12.5663706143592$$
$$x_{71} = -18.0641577581413$$
$$x_{72} = -54.1924732744239$$
$$x_{73} = 3.92699081698724$$
$$x_{74} = 6.28318530717959$$
$$x_{75} = -79.3252145031423$$
$$x_{76} = -99.7455667514759$$
$$x_{77} = -30.6305283725005$$
$$x_{78} = 10.2101761241668$$
$$x_{79} = 19.6349540849362$$
$$x_{80} = -77.7544181763474$$
$$x_{81} = -69.9004365423729$$
$$x_{82} = 43.9822971502571$$
$$x_{83} = -65.9734457253857$$
$$x_{84} = 172.002197784041$$
$$x_{85} = 2.35619449019234$$
$$x_{86} = -24.3473430653209$$
$$x_{87} = 90.3207887907066$$
$$x_{88} = -32.2013246992954$$
$$x_{89} = 72.2566310325652$$