El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\frac{\sin{\left(2 x \right)}}{2} + \frac{\sin{\left(4 x \right)}}{4} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = - \frac{\pi}{2}$$
$$x_{3} = \frac{\pi}{2}$$
$$x_{4} = \pi$$
Solución numérica$$x_{1} = 92.6769015135963$$
$$x_{2} = -76.9690105563921$$
$$x_{3} = 10.9955332899392$$
$$x_{4} = 42.4114622637135$$
$$x_{5} = 83.2522440509532$$
$$x_{6} = -36.1282773149103$$
$$x_{7} = -59.6902604182061$$
$$x_{8} = 21.9911485751286$$
$$x_{9} = 43.9822971502571$$
$$x_{10} = 15.707963267949$$
$$x_{11} = 80.1105845138607$$
$$x_{12} = -92.6769039529977$$
$$x_{13} = -70.6857580728809$$
$$x_{14} = -6.28318530717959$$
$$x_{15} = 78.5398163397448$$
$$x_{16} = -48.694612644595$$
$$x_{17} = -58.1194280780384$$
$$x_{18} = 73.8274757296551$$
$$x_{19} = -80.1105788980654$$
$$x_{20} = -98.9601412823446$$
$$x_{21} = 86.393763199972$$
$$x_{22} = 39.2699625294546$$
$$x_{23} = -7.85396947500705$$
$$x_{24} = 94.2477796076938$$
$$x_{25} = 76.9689583126707$$
$$x_{26} = 54.9778154903557$$
$$x_{27} = 64.4026127184382$$
$$x_{28} = -72.2566310325652$$
$$x_{29} = -73.8274110623715$$
$$x_{30} = 0$$
$$x_{31} = -89.5354399060464$$
$$x_{32} = 58.119460355203$$
$$x_{33} = 7.85402405072815$$
$$x_{34} = -50.2654824574367$$
$$x_{35} = -81.6814089933346$$
$$x_{36} = 36.1283177718334$$
$$x_{37} = -45.5531392890525$$
$$x_{38} = 29.8451746577235$$
$$x_{39} = -4.71232350291727$$
$$x_{40} = 98.9601020312679$$
$$x_{41} = -87.9645943005142$$
$$x_{42} = 70.6857520123693$$
$$x_{43} = 6.28318530717959$$
$$x_{44} = -26.7034677530648$$
$$x_{45} = -29.8451153120949$$
$$x_{46} = -42.4114150971255$$
$$x_{47} = -95.8185603541765$$
$$x_{48} = -64.4025645467213$$
$$x_{49} = -37.6991118430775$$
$$x_{50} = -14.137126606106$$
$$x_{51} = -10.9956056230913$$
$$x_{52} = 95.8186261978189$$
$$x_{53} = -67.5442896108627$$
$$x_{54} = 65.9734457253857$$
$$x_{55} = 17.278819977127$$
$$x_{56} = -86.3937140390016$$
$$x_{57} = -28.2743338823081$$
$$x_{58} = -23.5619889406814$$
$$x_{59} = 72.2566310325652$$
$$x_{60} = -43.9822971502571$$
$$x_{61} = -70.6858973800224$$
$$x_{62} = 48.6946025534402$$
$$x_{63} = -54.9778777514084$$
$$x_{64} = 26.7034531382938$$
$$x_{65} = 20.4203118356713$$
$$x_{66} = 87.9645943005142$$
$$x_{67} = -51.8362626096794$$
$$x_{68} = 100.530964914873$$
$$x_{69} = 14.137174780924$$
$$x_{70} = 28.2743338823081$$
$$x_{71} = 51.8363252167958$$
$$x_{72} = -94.2477796076938$$
$$x_{73} = -32.9867427226641$$
$$x_{74} = -1.57083856577707$$
$$x_{75} = -51.8362993417633$$
$$x_{76} = -21.9911485751286$$
$$x_{77} = 56.5486677646163$$
$$x_{78} = -65.9734457253857$$
$$x_{79} = -15.707963267949$$
$$x_{80} = 4.71230376855396$$
$$x_{81} = 80.110603596332$$
$$x_{82} = -17.278845553998$$
$$x_{83} = 50.2654824574367$$
$$x_{84} = 32.986673744333$$
$$x_{85} = 37.6991118430775$$
$$x_{86} = 61.2611039630468$$