El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\left(\cos^{2}{\left(x \right)} - 6 \cos{\left(x \right)}\right) + 5 = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = 2 \pi$$
Solución numérica$$x_{1} = -50.2654824374308$$
$$x_{2} = -37.6991110957083$$
$$x_{3} = 62.8318527649925$$
$$x_{4} = 18.8495556060838$$
$$x_{5} = -94.2477803043159$$
$$x_{6} = -43.9822971745197$$
$$x_{7} = 100.530964756634$$
$$x_{8} = 50.2654817613617$$
$$x_{9} = -56.5486684790069$$
$$x_{10} = -12.5663712004678$$
$$x_{11} = -94.2477791104754$$
$$x_{12} = 6.28318528418766$$
$$x_{13} = -6.28318486744501$$
$$x_{14} = -75.3982239795059$$
$$x_{15} = -18.8495563817765$$
$$x_{16} = -56.5486674467976$$
$$x_{17} = -43.9822978885728$$
$$x_{18} = 50.2654832067213$$
$$x_{19} = 12.566371311739$$
$$x_{20} = 94.2477796093522$$
$$x_{21} = -50.2654831492798$$
$$x_{22} = -50.2654822821048$$
$$x_{23} = 25.1327407768041$$
$$x_{24} = -81.6814096629354$$
$$x_{25} = -25.1327409948856$$
$$x_{26} = -69.115038711708$$
$$x_{27} = 56.5486684669242$$
$$x_{28} = -37.6991125224341$$
$$x_{29} = -31.415926720702$$
$$x_{30} = -56.5486683579557$$
$$x_{31} = 69.1150379354198$$
$$x_{32} = 87.9645943359769$$
$$x_{33} = 56.548667353662$$
$$x_{34} = -87.9645935803486$$
$$x_{35} = 31.4159268711656$$
$$x_{36} = 219.911485926273$$
$$x_{37} = 75.3982240301256$$
$$x_{38} = -94.2477794416279$$
$$x_{39} = 94.2477803574094$$
$$x_{40} = -25.132740638504$$
$$x_{41} = -62.8318535403192$$
$$x_{42} = 43.9822978498098$$
$$x_{43} = -6.28318599404732$$
$$x_{44} = 12.5663702389676$$
$$x_{45} = 37.6991122499315$$
$$x_{46} = 87.9645935651708$$
$$x_{47} = -100.53096546582$$
$$x_{48} = -87.9645943585387$$
$$x_{49} = 43.9822964135666$$
$$x_{50} = -75.3982238797599$$
$$x_{51} = 0$$
$$x_{52} = -31.4159258436316$$
$$x_{53} = -87.9645950390744$$
$$x_{54} = -62.8318526165178$$
$$x_{55} = 81.6814093641414$$
$$x_{56} = 6.28318461901929$$
$$x_{57} = -75.3982229991808$$
$$x_{58} = -81.6814082474214$$
$$x_{59} = -81.6814090383354$$
$$x_{60} = -37.6991118773175$$
$$x_{61} = 18.8495565190348$$
$$x_{62} = -69.1150377961362$$
$$x_{63} = 50.2654824463352$$
$$x_{64} = 12.5663704383801$$
$$x_{65} = 31.4159259571154$$
$$x_{66} = -100.5309646058$$
$$x_{67} = -18.8495554578922$$
$$x_{68} = 56.5486675974905$$
$$x_{69} = 37.6991111613739$$
$$x_{70} = 25.1327417006947$$
$$x_{71} = 81.6814091960444$$
$$x_{72} = 75.3982231147894$$
$$x_{73} = 62.831853676476$$
$$x_{74} = -43.982296436222$$
$$x_{75} = 81.6814083169764$$
$$x_{76} = -12.5663702878089$$
$$x_{77} = -50.2654819876724$$
$$x_{78} = 43.982297169483$$
$$x_{79} = 37.6991120367204$$
$$x_{80} = 6.28318605567716$$
$$x_{81} = 87.9645949916168$$
$$x_{82} = -25.1327415528166$$
$$x_{83} = 69.1150388592403$$
$$x_{84} = -31.415926872226$$
$$x_{85} = 94.2477789045357$$
$$x_{86} = -6.28318512265937$$
$$x_{87} = 100.530964471502$$