El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\left|{\sin{\left(2 x \right)} \cos{\left(x \right)}}\right| = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = \frac{\pi}{2}$$
$$x_{3} = \frac{3 \pi}{2}$$
Solución numérica$$x_{1} = 65.9734457253857$$
$$x_{2} = 7.85398151962477$$
$$x_{3} = 67.5442422018325$$
$$x_{4} = -36.128315423197$$
$$x_{5} = -95.818575595671$$
$$x_{6} = -61.261056881309$$
$$x_{7} = -29.8451300981866$$
$$x_{8} = 48.6946859820148$$
$$x_{9} = -59.6902604182061$$
$$x_{10} = 36.1283155526489$$
$$x_{11} = -21.9911485751286$$
$$x_{12} = -102.101761529878$$
$$x_{13} = 21.9911485751286$$
$$x_{14} = -86.3937978155375$$
$$x_{15} = -51.8362786906154$$
$$x_{16} = -42.4115006663339$$
$$x_{17} = -1.57079642505341$$
$$x_{18} = 51.8362788934209$$
$$x_{19} = 95.8185760508519$$
$$x_{20} = 23.5619450555027$$
$$x_{21} = 14.1371670924752$$
$$x_{22} = -25.1327412287183$$
$$x_{23} = -58.1194640027517$$
$$x_{24} = -26.7035373477012$$
$$x_{25} = -83.2522054524035$$
$$x_{26} = -92.6769826606235$$
$$x_{27} = -15.707963267949$$
$$x_{28} = -73.8274272804402$$
$$x_{29} = -7.85398168893896$$
$$x_{30} = -95.8185758682892$$
$$x_{31} = -80.1106125824842$$
$$x_{32} = -45.5530935824522$$
$$x_{33} = -81.6814089933346$$
$$x_{34} = 20.4203521537986$$
$$x_{35} = -64.4026492408158$$
$$x_{36} = 92.6769831301454$$
$$x_{37} = -65.9734457253857$$
$$x_{38} = 4.71238883532779$$
$$x_{39} = 0$$
$$x_{40} = -17.278759737384$$
$$x_{41} = 73.8274274722061$$
$$x_{42} = -23.561945003804$$
$$x_{43} = 45.5530936288414$$
$$x_{44} = 89.5353907744432$$
$$x_{45} = -92.6769836764771$$
$$x_{46} = 80.1106131546315$$
$$x_{47} = 6.28318530717959$$
$$x_{48} = -67.5442421609972$$
$$x_{49} = 87.9645943005142$$
$$x_{50} = 26.7035374084741$$
$$x_{51} = 86.3937978909611$$
$$x_{52} = 29.8451303144929$$
$$x_{53} = 72.2566310325652$$
$$x_{54} = 7.85398173541774$$
$$x_{55} = 43.9822971502571$$
$$x_{56} = -89.5353907394375$$
$$x_{57} = -86.3937986622393$$
$$x_{58} = -70.6858349962623$$
$$x_{59} = -20.4203520921076$$
$$x_{60} = 1.57079648184495$$
$$x_{61} = -7.85398150264842$$
$$x_{62} = -39.2699083096144$$
$$x_{63} = -87.9645943005142$$
$$x_{64} = 70.6858345559153$$
$$x_{65} = 50.2654824574367$$
$$x_{66} = -37.6991118430775$$
$$x_{67} = -43.9822971502571$$
$$x_{68} = 42.4115007327518$$
$$x_{69} = 28.2743338823081$$
$$x_{70} = 94.2477796076938$$
$$x_{71} = 64.4026493118058$$
$$x_{72} = -14.13716684381$$