El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\left|{\cos{\left(x \right)}}\right| - 1 = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = \pi$$
$$x_{3} = 2 \pi$$
Solución numérica$$x_{1} = -18.8495555173448$$
$$x_{2} = -47.1238901083229$$
$$x_{3} = 3.14159211708139$$
$$x_{4} = -21.9911485864417$$
$$x_{5} = -56.5486674685864$$
$$x_{6} = -84.8230020565447$$
$$x_{7} = -43.9822971745392$$
$$x_{8} = -18.8495563230046$$
$$x_{9} = 81.6814091897036$$
$$x_{10} = -78.5398160472843$$
$$x_{11} = -40.8407049008781$$
$$x_{12} = -37.6991118772631$$
$$x_{13} = -97.3893724533348$$
$$x_{14} = -31.4159267157965$$
$$x_{15} = -34.5575188899093$$
$$x_{16} = 25.1327408328211$$
$$x_{17} = -28.2743337069329$$
$$x_{18} = 12.5663704426592$$
$$x_{19} = 31.4159268459961$$
$$x_{20} = -69.1150386869085$$
$$x_{21} = 40.8407049800347$$
$$x_{22} = 65.9734457529812$$
$$x_{23} = 62.8318535568358$$
$$x_{24} = 91.1061873718352$$
$$x_{25} = 91.1061865667532$$
$$x_{26} = -91.1061864815274$$
$$x_{27} = -12.5663705813442$$
$$x_{28} = 25.1327416384075$$
$$x_{29} = -3.14159295109225$$
$$x_{30} = -100.530964626003$$
$$x_{31} = -47.1238893275319$$
$$x_{32} = -65.9734457649277$$
$$x_{33} = 75.3982240031607$$
$$x_{34} = -78.5398168194507$$
$$x_{35} = -3.14159217367683$$
$$x_{36} = 94.2477796093523$$
$$x_{37} = -91.106187265474$$
$$x_{38} = 9.42477826738203$$
$$x_{39} = 62.8318527849002$$
$$x_{40} = 34.5575190219169$$
$$x_{41} = -72.2566308657983$$
$$x_{42} = 0$$
$$x_{43} = 50.2654824463392$$
$$x_{44} = 47.123889410773$$
$$x_{45} = -81.6814093609983$$
$$x_{46} = 78.5398161804942$$
$$x_{47} = -25.1327407505866$$
$$x_{48} = 87.964594335905$$
$$x_{49} = 18.8495564031971$$
$$x_{50} = 15.7079634518075$$
$$x_{51} = -12.5663703112531$$
$$x_{52} = -59.6902604578012$$
$$x_{53} = -75.3982238741744$$
$$x_{54} = -62.8318534787248$$
$$x_{55} = -37.6991128371258$$
$$x_{56} = 59.6902606104322$$
$$x_{57} = 31.4159260648825$$
$$x_{58} = -94.2477794452815$$
$$x_{59} = -97.3893729145565$$
$$x_{60} = 69.1150379887504$$
$$x_{61} = 53.407075424589$$
$$x_{62} = 84.8230013636028$$
$$x_{63} = 75.3982232188727$$
$$x_{64} = -56.5486682426592$$
$$x_{65} = 6.28318528420851$$
$$x_{66} = -25.1327415297174$$
$$x_{67} = 97.3893717959212$$
$$x_{68} = -12.5663710889626$$
$$x_{69} = 43.9822971694647$$
$$x_{70} = 100.530964759815$$
$$x_{71} = -69.1150379045123$$
$$x_{72} = 69.115038794053$$
$$x_{73} = -50.2654822863493$$
$$x_{74} = -34.5575196658297$$
$$x_{75} = 37.6991120311338$$
$$x_{76} = -12.5663715061514$$
$$x_{77} = 18.8495556275525$$
$$x_{78} = 97.389372581711$$
$$x_{79} = 9.42477748794163$$
$$x_{80} = -84.8230012511693$$
$$x_{81} = 3.14159306054457$$
$$x_{82} = 72.2566310277176$$
$$x_{83} = 56.5486676011951$$
$$x_{84} = -75.3982221405918$$
$$x_{85} = -15.7079632965989$$
$$x_{86} = 21.9911485852059$$
$$x_{87} = -6.2831851275477$$
$$x_{88} = -81.6814090382277$$
$$x_{89} = 47.1238902162437$$
$$x_{90} = 40.8407042062167$$
$$x_{91} = -87.9645943586158$$
$$x_{92} = 84.8230021335997$$
$$x_{93} = -9.4247781365785$$
$$x_{94} = 28.2743338651796$$
$$x_{95} = -53.407075294995$$
$$x_{96} = -62.831852673202$$
$$x_{97} = 53.4070746418597$$
$$x_{98} = -40.8407040952604$$
$$x_{99} = 3.1415922548952$$
$$x_{100} = 87.9645942336512$$