El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sin{\left(\frac{x}{4} \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = 4 \pi$$
Solución numérica$$x_{1} = -75.398223686155$$
$$x_{2} = -62.8318530717959$$
$$x_{3} = 87.9645943005142$$
$$x_{4} = 188.495559215388$$
$$x_{5} = -87.9645943005142$$
$$x_{6} = 100.530964914873$$
$$x_{7} = 62.8318530717959$$
$$x_{8} = 12.5663706143592$$
$$x_{9} = 25.1327412287183$$
$$x_{10} = -37.6991118430775$$
$$x_{11} = -17002.299441228$$
$$x_{12} = 490.088453960008$$
$$x_{13} = -100.530964914873$$
$$x_{14} = -929.911425462579$$
$$x_{15} = 0$$
$$x_{16} = -12.5663706143592$$
$$x_{17} = 75.398223686155$$
$$x_{18} = 2927.96435314569$$
$$x_{19} = -50.2654824574367$$
$$x_{20} = 50.2654824574367$$
$$x_{21} = 37.6991118430775$$
$$x_{22} = -25.1327412287183$$