El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$3 \cos{\left(x + \frac{\pi}{6} \right)} - 2 = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{\pi}{6} + \operatorname{acos}{\left(\frac{2}{3} \right)}$$
$$x_{2} = - \operatorname{acos}{\left(\frac{2}{3} \right)} + \frac{11 \pi}{6}$$
Solución numérica$$x_{1} = 4.91851786101336$$
$$x_{2} = 88.2820641954838$$
$$x_{3} = -64.1965205179621$$
$$x_{4} = -93.9303097127242$$
$$x_{5} = 69.4325082739451$$
$$x_{6} = -51.6301499036029$$
$$x_{7} = 56.8661376595859$$
$$x_{8} = 6.60065520214922$$
$$x_{9} = 81.9988788883043$$
$$x_{10} = -87.6471244055446$$
$$x_{11} = -32.7805939820642$$
$$x_{12} = -83.0460764395009$$
$$x_{13} = 63.1493229667655$$
$$x_{14} = 17.4848884753725$$
$$x_{15} = 61.4671856256296$$
$$x_{16} = -2910.47946467031$$
$$x_{17} = 23.7680737825521$$
$$x_{18} = -1.36466744616623$$
$$x_{19} = -45.3469645964233$$
$$x_{20} = -20.214223367705$$
$$x_{21} = 86.599926854348$$
$$x_{22} = -76.7628911323213$$
$$x_{23} = 75.7156935811247$$
$$x_{24} = 12.8838405093288$$
$$x_{25} = 74.0335562399888$$
$$x_{26} = -68.7975684840058$$
$$x_{27} = -39.0637792892437$$
$$x_{28} = -75.0807537911854$$
$$x_{29} = -81.363939098365$$
$$x_{30} = 12861.9977936916$$
$$x_{31} = -70.4797058251417$$
$$x_{32} = -5.96571541220996$$
$$x_{33} = 55.18400031845$$
$$x_{34} = -43.6648272552875$$
$$x_{35} = 19.1670258165084$$
$$x_{36} = 100.848434809843$$
$$x_{37} = -56.2311978696466$$
$$x_{38} = 92.8831121615276$$
$$x_{39} = 80.3167415471684$$
$$x_{40} = -57.9133352107825$$
$$x_{41} = 30.0512590897317$$
$$x_{42} = 50.5829523524063$$
$$x_{43} = 44.2997670452267$$
$$x_{44} = -12.2489007193895$$
$$x_{45} = -26.4974086748846$$
$$x_{46} = 36.3344443969113$$
$$x_{47} = -13.9310380605254$$
$$x_{48} = 11.2017031681929$$
$$x_{49} = -62.5143831768262$$
$$x_{50} = -100.213495019904$$
$$x_{51} = 25.450211123688$$
$$x_{52} = 0.317469894969631$$
$$x_{53} = 38.0165817380472$$
$$x_{54} = -31.0984566409283$$
$$x_{55} = -95.61244705386$$
$$x_{56} = 42.6176297040909$$
$$x_{57} = 99.1662974687072$$
$$x_{58} = -7.64785275334582$$
$$x_{59} = -37.3816419481079$$
$$x_{60} = -49.9480125624671$$
$$x_{61} = 31.7333964308676$$
$$x_{62} = -18.5320860265691$$
$$x_{63} = -89.3292617466804$$
$$x_{64} = -24.8152713337487$$
$$x_{65} = 94.5652495026634$$
$$x_{66} = 67.7503709328092$$
$$x_{67} = 48.9008150112705$$