El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cos{\left(3 x - 2 \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \frac{2}{3} + \frac{\pi}{2}$$
$$x_{2} = \frac{\pi}{6} + \frac{2}{3}$$
Solución numérica$$x_{1} = -92.0103166142322$$
$$x_{2} = -67.9247729367105$$
$$x_{3} = -39.6504390544023$$
$$x_{4} = 83.9188719867962$$
$$x_{5} = 46.2197601437187$$
$$x_{6} = -59.5471925271377$$
$$x_{7} = 50.4085503485051$$
$$x_{8} = -89.915921511839$$
$$x_{9} = 96.4852426011554$$
$$x_{10} = -41.7448341567955$$
$$x_{11} = -85.7271313070526$$
$$x_{12} = 37.8421797341459$$
$$x_{13} = -30.225661093633$$
$$x_{14} = -70.0191680391037$$
$$x_{15} = 30.5117968757697$$
$$x_{16} = -83.6327362046595$$
$$x_{17} = -33.3672537472228$$
$$x_{18} = 20.0398213638037$$
$$x_{19} = -87.8215264094458$$
$$x_{20} = 92.296452396369$$
$$x_{21} = -19.753685581667$$
$$x_{22} = -65.8303778343173$$
$$x_{23} = -17.6592904792738$$
$$x_{24} = -13.4705002744874$$
$$x_{25} = 10.6150434030343$$
$$x_{26} = -15.5648953768806$$
$$x_{27} = 15.8510311590173$$
$$x_{28} = 13.7566360566241$$
$$x_{29} = -81.5383411022663$$
$$x_{30} = -35.461648849616$$
$$x_{31} = 44.1253650413255$$
$$x_{32} = -94.1047117166254$$
$$x_{33} = -48.0280194639751$$
$$x_{34} = 28.4174017733765$$
$$x_{35} = 90.2020572939758$$
$$x_{36} = -1.95132721132483$$
$$x_{37} = 26.3230066709833$$
$$x_{38} = -72.1135631414969$$
$$x_{39} = 81.824476884403$$
$$x_{40} = 4.33185809585476$$
$$x_{41} = -74.2079582438901$$
$$x_{42} = 24.2286115685901$$
$$x_{43} = 74.4940940260268$$
$$x_{44} = 39.9365748365391$$
$$x_{45} = 76.58848912842$$
$$x_{46} = 17.9454262614105$$
$$x_{47} = 88.1076621915826$$
$$x_{48} = 117.429193625087$$
$$x_{49} = 68.2109087188472$$
$$x_{50} = 35.7477846317527$$
$$x_{51} = 52.5029454508983$$
$$x_{52} = -61.6415876295309$$
$$x_{53} = 2.23746299346156$$
$$x_{54} = -79.4439459998731$$
$$x_{55} = 61.9277234116676$$
$$x_{56} = -98.2935019214118$$
$$x_{57} = -4.04572231371802$$
$$x_{58} = 72.3996989236336$$
$$x_{59} = -63.7359827319241$$
$$x_{60} = 0.143067891068368$$
$$x_{61} = 42.0309699389323$$
$$x_{62} = -76.3023533462833$$
$$x_{63} = 99.6268352547452$$
$$x_{64} = -6.14011741611122$$
$$x_{65} = 66.116513616454$$
$$x_{66} = -8.23451251850442$$
$$x_{67} = -50.1224145663683$$
$$x_{68} = -21.8480806840602$$
$$x_{69} = 53.5501430020949$$
$$x_{70} = -52.2168096687615$$
$$x_{71} = 6.42625319824795$$
$$x_{72} = -96.1991068190186$$
$$x_{73} = 59.8333283092744$$
$$x_{74} = 94.3908474987622$$
$$x_{75} = 86.0132670891894$$
$$x_{76} = 162.458688326541$$
$$x_{77} = -23.9424757864534$$
$$x_{78} = -45.9336243615819$$
$$x_{79} = 70.3053038212404$$
$$x_{80} = 8.52064830064115$$
$$x_{81} = -43.8392292591887$$
$$x_{82} = 64.0221185140608$$
$$x_{83} = 22.1342164661969$$
$$x_{84} = -37.5560439520091$$
$$x_{85} = -1148764.05142171$$
$$x_{86} = 57.7389332068812$$
$$x_{87} = -27.0840684400432$$
$$x_{88} = -28.1312659912398$$
$$x_{89} = 11.6622409542309$$
$$x_{90} = -57.4527974247445$$
$$x_{91} = 48.3141552461119$$
$$x_{92} = 79.7300817820098$$
$$x_{93} = -11.3761051720942$$
$$x_{94} = -26.0368708888466$$