El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$3 \cos{\left(\frac{x - \pi}{3} \right)} + 2 = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - 3 \operatorname{asin}{\left(\frac{2}{3} \right)} - \frac{\pi}{2}$$
$$x_{2} = 3 \operatorname{asin}{\left(\frac{2}{3} \right)} + \frac{5 \pi}{2}$$
Solución numérica$$x_{1} = 1824.64694509378$$
$$x_{2} = 28.8927205241941$$
$$x_{3} = 90.487800312218$$
$$x_{4} = 47.7422764457329$$
$$x_{5} = -1247.83067011703$$
$$x_{6} = 33.9391325476017$$
$$x_{7} = -8.80639131888338$$
$$x_{8} = -3.7599792954758$$
$$x_{9} = -65.3550590834997$$
$$x_{10} = 269049.754832725$$
$$x_{11} = 15.089576626063$$
$$x_{12} = -41.4590911385533$$
$$x_{13} = -27.6559472404221$$
$$x_{14} = 52.7886884691405$$
$$x_{15} = 104.290944210349$$
$$x_{16} = 10.0431646026554$$
$$x_{17} = -22.6095352170146$$
$$x_{18} = 71.6382443906792$$
$$x_{19} = 66.5918323672717$$
$$x_{20} = -84.2046150050384$$
$$x_{21} = -46.5055031619609$$
$$x_{22} = 575.529842248818$$
$$x_{23} = -98.0077589031696$$
$$x_{24} = 85.4413882888104$$
$$x_{25} = -79.1582029816308$$
$$x_{26} = -60.3086470600921$$