El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$2 \cos{\left(x \right)} + \frac{3}{2} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \operatorname{acos}{\left(- \frac{3}{4} \right)} + 2 \pi$$
$$x_{2} = \operatorname{acos}{\left(- \frac{3}{4} \right)}$$
Solución numérica$$x_{1} = 72.9793652803787$$
$$x_{2} = 21.2684143273151$$
$$x_{3} = -84.100267399111$$
$$x_{4} = 46.4011555560335$$
$$x_{5} = 54.1298093588399$$
$$x_{6} = -54.1298093588399$$
$$x_{7} = -91.8289212019174$$
$$x_{8} = 14.9852290201356$$
$$x_{9} = -90.3834527062906$$
$$x_{10} = 16.4306975157624$$
$$x_{11} = 65.2507114775722$$
$$x_{12} = 35.2802534373011$$
$$x_{13} = 52.6843408632131$$
$$x_{14} = -8.70204371295596$$
$$x_{15} = 71.5338967847518$$
$$x_{16} = 10.1475122085828$$
$$x_{17} = 2.41885840577638$$
$$x_{18} = -33.8347849416743$$
$$x_{19} = -72.9793652803787$$
$$x_{20} = -14.9852290201356$$
$$x_{21} = -77.8170820919314$$
$$x_{22} = 8.70204371295596$$
$$x_{23} = -79.2625505875583$$
$$x_{24} = -58.9675261703927$$
$$x_{25} = 98.112106509097$$
$$x_{26} = -52.6843408632131$$
$$x_{27} = -71.5338967847518$$
$$x_{28} = 66.6961799731991$$
$$x_{29} = 91.8289212019174$$
$$x_{30} = -85.5457358947378$$
$$x_{31} = 385.693162143731$$
$$x_{32} = 85.5457358947378$$
$$x_{33} = 22.713882822942$$
$$x_{34} = 79.2625505875583$$
$$x_{35} = -66.6961799731991$$
$$x_{36} = -3.86432690140321$$
$$x_{37} = -60.4129946660195$$
$$x_{38} = 58.9675261703927$$
$$x_{39} = -41.5634387444807$$
$$x_{40} = 27.5515996344947$$
$$x_{41} = 40.1179702488539$$
$$x_{42} = 77.8170820919314$$
$$x_{43} = 90.3834527062906$$
$$x_{44} = 28.9970681301216$$
$$x_{45} = -98.112106509097$$
$$x_{46} = -27.5515996344947$$
$$x_{47} = -22.713882822942$$
$$x_{48} = -46.4011555560335$$
$$x_{49} = -65.2507114775722$$
$$x_{50} = 33.8347849416743$$
$$x_{51} = -40.1179702488539$$
$$x_{52} = -10.1475122085828$$
$$x_{53} = -47.8466240516603$$
$$x_{54} = 3.86432690140321$$
$$x_{55} = -21.2684143273151$$
$$x_{56} = 60.4129946660195$$
$$x_{57} = 123.244847737815$$
$$x_{58} = -16.4306975157624$$
$$x_{59} = 105094.976306292$$
$$x_{60} = 96.6666380134702$$
$$x_{61} = -28.9970681301216$$
$$x_{62} = -2.41885840577638$$
$$x_{63} = 41.5634387444807$$
$$x_{64} = -96.6666380134702$$
$$x_{65} = 47.8466240516603$$
$$x_{66} = 84.100267399111$$
$$x_{67} = -35.2802534373011$$