El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\log{\left(- \cos{\left(x \right)} \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \pi$$
Solución numérica$$x_{1} = -59.690260391105$$
$$x_{2} = -65.9734457648386$$
$$x_{3} = 59.6902599988118$$
$$x_{4} = 3.14159236458576$$
$$x_{5} = -40.8407039100223$$
$$x_{6} = -28.2743336970608$$
$$x_{7} = -53.4070753064322$$
$$x_{8} = 3.1415932585699$$
$$x_{9} = 84.823002805596$$
$$x_{10} = 28.2743338651582$$
$$x_{11} = -21.9911486223098$$
$$x_{12} = -47.1238901689402$$
$$x_{13} = 91.1061876923931$$
$$x_{14} = -84.823002057095$$
$$x_{15} = -9.42477771481239$$
$$x_{16} = -28.2743342244749$$
$$x_{17} = -84.823001441919$$
$$x_{18} = -65.9734457642993$$
$$x_{19} = -34.5575202359721$$
$$x_{20} = 9.42477832891555$$
$$x_{21} = 15.7079634632083$$
$$x_{22} = -34.5575188333352$$
$$x_{23} = 3.14159329215353$$
$$x_{24} = 72.2566310277163$$
$$x_{25} = 65.9734456596322$$
$$x_{26} = 40.8407056026057$$
$$x_{27} = 53.4070754913975$$
$$x_{28} = 21.9911485190215$$
$$x_{29} = 47.1238895754234$$
$$x_{30} = 40.8407041550563$$
$$x_{31} = -84.8230010779785$$
$$x_{32} = -15.7079632493787$$
$$x_{33} = 3.14159207244778$$
$$x_{34} = -72.2566313408537$$
$$x_{35} = -97.3893719631857$$
$$x_{36} = -3.14159159553391$$
$$x_{37} = -97.3893724664065$$
$$x_{38} = 47.1238892401961$$
$$x_{39} = 97.3893713350675$$
$$x_{40} = -9.42477814652397$$
$$x_{41} = -59.6902604579606$$
$$x_{42} = 9.4247769576896$$
$$x_{43} = 53.4070741096774$$
$$x_{44} = 47.1238904278493$$
$$x_{45} = -34.5575201938684$$
$$x_{46} = -91.1061873312798$$
$$x_{47} = -53.4070748400409$$
$$x_{48} = 91.106187597873$$
$$x_{49} = 34.5575190133278$$
$$x_{50} = 78.5398165412932$$
$$x_{51} = 34.5575194123513$$
$$x_{52} = -78.5398173320079$$
$$x_{53} = -40.8407043026032$$
$$x_{54} = 97.3893712747287$$
$$x_{55} = -3.14159300683281$$
$$x_{56} = 97.389372654126$$
$$x_{57} = 47.1238904934905$$
$$x_{58} = -47.1238889150739$$
$$x_{59} = 40.8407053136288$$
$$x_{60} = 21.9911485852153$$
$$x_{61} = 53.4070741478622$$
$$x_{62} = -40.8407048462995$$
$$x_{63} = -91.1061860368827$$
$$x_{64} = -72.256630857317$$
$$x_{65} = 91.1061869569737$$
$$x_{66} = -91.1061859802604$$
$$x_{67} = 65.9734457530642$$
$$x_{68} = 15.7079628887667$$
$$x_{69} = 84.8230024224715$$
$$x_{70} = -78.5398159953694$$
$$x_{71} = 72.2566310354099$$
$$x_{72} = -78.5398174338057$$
$$x_{73} = 9.42477695336787$$
$$x_{74} = -3.14159179855115$$
$$x_{75} = -47.1238887896178$$
$$x_{76} = -15.7079632966706$$
$$x_{77} = 59.6902606235069$$
$$x_{78} = 84.82300131674$$
$$x_{79} = -21.991148586432$$
$$x_{80} = 28.274333892804$$
$$x_{81} = -40.8407050959251$$
$$x_{82} = -84.8230022649727$$
$$x_{83} = 91.1061864073649$$
$$x_{84} = 78.5398161731332$$