El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\frac{\log{\left(\cos{\left(x \right)} \right)}}{\log{\left(2 \right)}} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = 2 \pi$$
Solución numérica$$x_{1} = -12.5663716386669$$
$$x_{2} = 18.8495555741382$$
$$x_{3} = 75.39822407273$$
$$x_{4} = 100.530964753022$$
$$x_{5} = 18.8495570029843$$
$$x_{6} = -62.8318534517187$$
$$x_{7} = 75.3982226911418$$
$$x_{8} = 69.1150381807919$$
$$x_{9} = -6.28318511692891$$
$$x_{10} = 25.1327406563971$$
$$x_{11} = 0$$
$$x_{12} = 75.3982227418079$$
$$x_{13} = -18.8495557286473$$
$$x_{14} = -18.8495553258088$$
$$x_{15} = -25.1327401930409$$
$$x_{16} = -56.5486674143785$$
$$x_{17} = -69.1150387500801$$
$$x_{18} = 81.681409203672$$
$$x_{19} = 69.1150390932802$$
$$x_{20} = 25.1327418431203$$
$$x_{21} = 50.2654824463311$$
$$x_{22} = 25.1327418930934$$
$$x_{23} = 87.9645943360512$$
$$x_{24} = 31.4159255531763$$
$$x_{25} = 62.8318542034359$$
$$x_{26} = -50.2654822771894$$
$$x_{27} = -94.2477794374461$$
$$x_{28} = -87.9645943584596$$
$$x_{29} = 37.6991120433529$$
$$x_{30} = -37.6991118773736$$
$$x_{31} = -75.3982238864105$$
$$x_{32} = -18.8495562408585$$
$$x_{33} = 31.4159255304025$$
$$x_{34} = 12.5663704334084$$
$$x_{35} = -43.9822971744998$$
$$x_{36} = 6.28318528416623$$
$$x_{37} = -100.53096457631$$
$$x_{38} = 69.1150390127643$$
$$x_{39} = 69.1150378238503$$
$$x_{40} = 43.9822971695019$$
$$x_{41} = -31.4159267264704$$
$$x_{42} = -56.5486688343165$$
$$x_{43} = 62.831852735923$$
$$x_{44} = -25.1327415878584$$
$$x_{45} = 25.1327409700176$$
$$x_{46} = -18.8495565116576$$
$$x_{47} = -81.6814090384469$$
$$x_{48} = -12.5663702522378$$
$$x_{49} = 31.4159269101267$$
$$x_{50} = 94.2477796093522$$
$$x_{51} = 56.5486675932357$$
$$x_{52} = -62.8318524940769$$
$$x_{53} = -62.8318536803612$$
$$x_{54} = -69.1150373853363$$
$$x_{55} = -62.8318528736237$$