Graph of the function intersects the axis X at f = 0
so we need to solve the equation:
$$\log{\left(\cos^{2}{\left(x \right)} \right)} = 0$$
Solve this equationThe points of intersection with the axis X:
Analytical solution$$x_{1} = 0$$
$$x_{2} = \pi$$
$$x_{3} = 2 \pi$$
Numerical solution$$x_{1} = -50.2654822771894$$
$$x_{2} = -72.256630857317$$
$$x_{3} = 53.4070754913975$$
$$x_{4} = 40.8407041550563$$
$$x_{5} = 3.14159207244778$$
$$x_{6} = -15.7079632966706$$
$$x_{7} = -75.3982226597999$$
$$x_{8} = 28.2743338651582$$
$$x_{9} = 91.106187597873$$
$$x_{10} = 78.5398161731332$$
$$x_{11} = 37.6991120433529$$
$$x_{12} = 34.5575190133278$$
$$x_{13} = -94.2477794374461$$
$$x_{14} = -56.5486688343165$$
$$x_{15} = -9.42477796310118$$
$$x_{16} = 72.2566310277163$$
$$x_{17} = -62.8318536803612$$
$$x_{18} = 75.39822407273$$
$$x_{19} = -18.8495565116576$$
$$x_{20} = -34.5575202359721$$
$$x_{21} = -87.9645943584596$$
$$x_{22} = 100.530964753022$$
$$x_{23} = 47.1238892401961$$
$$x_{24} = 21.9911485852153$$
$$x_{25} = -47.1238887896178$$
$$x_{26} = -3.14159159553391$$
$$x_{27} = -43.9822971744998$$
$$x_{28} = -84.8230022649727$$
$$x_{29} = -40.8407050959251$$
$$x_{30} = 56.5486675932357$$
$$x_{31} = 50.2654824463311$$
$$x_{32} = -34.5575188333352$$
$$x_{33} = -6.28318511692891$$
$$x_{34} = 59.6902606235069$$
$$x_{35} = 31.4159269101267$$
$$x_{36} = -3.14159300683281$$
$$x_{37} = 62.8318542034359$$
$$x_{38} = 9.42477834784266$$
$$x_{39} = -37.6991118773736$$
$$x_{40} = 18.8495570029843$$
$$x_{41} = -78.5398174338057$$
$$x_{42} = -47.1238901689402$$
$$x_{43} = 91.1061864073649$$
$$x_{44} = -12.5663716386669$$
$$x_{45} = -9.42477814652397$$
$$x_{46} = -69.1150373853363$$
$$x_{47} = -31.4159260171396$$
$$x_{48} = -75.3982238864105$$
$$x_{49} = 6.28318528416623$$
$$x_{50} = 25.1327406563971$$
$$x_{51} = -31.4159267264704$$
$$x_{52} = 12.5663704334084$$
$$x_{53} = -78.5398159953694$$
$$x_{54} = -53.4070753064322$$
$$x_{55} = -56.5486674143785$$
$$x_{56} = -53.4070742959952$$
$$x_{57} = -91.1061873312798$$
$$x_{58} = 69.1150378238503$$
$$x_{59} = 18.8495555741382$$
$$x_{60} = -84.8230010779785$$
$$x_{61} = -25.1327401930409$$
$$x_{62} = -21.991148586432$$
$$x_{63} = 94.2477796093522$$
$$x_{64} = 15.7079634632083$$
$$x_{65} = -18.8495553258088$$
$$x_{66} = 81.681409203672$$
$$x_{67} = 9.42477832891555$$
$$x_{68} = 0$$
$$x_{69} = 84.82300131674$$
$$x_{70} = -12.5663702522378$$
$$x_{71} = 69.1150390127643$$
$$x_{72} = -28.2743336970608$$
$$x_{73} = -59.6902604579606$$
$$x_{74} = 40.8407056026057$$
$$x_{75} = -25.1327415878584$$
$$x_{76} = -65.9734457648386$$
$$x_{77} = -97.3893724664065$$
$$x_{78} = 47.1238904278493$$
$$x_{79} = 3.1415932585699$$
$$x_{80} = 62.831852735923$$
$$x_{81} = -91.1061859802604$$
$$x_{82} = 53.4070741478622$$
$$x_{83} = -69.1150387500801$$
$$x_{84} = 87.9645943360512$$
$$x_{85} = -81.6814090384469$$
$$x_{86} = 75.3982227418079$$
$$x_{87} = -40.8407039100223$$
$$x_{88} = -62.8318524940769$$
$$x_{89} = 25.1327418431203$$
$$x_{90} = 97.3893713350675$$
$$x_{91} = 65.9734457530642$$
$$x_{92} = 9.4247769576896$$
$$x_{93} = 97.389372654126$$
$$x_{94} = -100.53096457631$$
$$x_{95} = 43.9822971695019$$
$$x_{96} = 31.4159255531763$$