El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sqrt{\cos{\left(x \right)}} - 1 = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = 2 \pi$$
Solución numérica$$x_{1} = 75.3982230005459$$
$$x_{2} = 37.6991120372048$$
$$x_{3} = -87.9645950929021$$
$$x_{4} = -18.8495564135118$$
$$x_{5} = 31.415925831963$$
$$x_{6} = -12.566370282398$$
$$x_{7} = -81.681409721359$$
$$x_{8} = -6.28318417219824$$
$$x_{9} = 6.28318605887065$$
$$x_{10} = 37.6991130258393$$
$$x_{11} = -62.8318535752407$$
$$x_{12} = -62.8318525880556$$
$$x_{13} = 56.5486690068509$$
$$x_{14} = 75.398224037078$$
$$x_{15} = 62.8318527607399$$
$$x_{16} = 18.8495566668243$$
$$x_{17} = -81.6814090383376$$
$$x_{18} = -100.53096460164$$
$$x_{19} = 81.6814102261652$$
$$x_{20} = -75.3982224535388$$
$$x_{21} = 81.6814091966381$$
$$x_{22} = 87.9645934220767$$
$$x_{23} = 81.6814078379838$$
$$x_{24} = 50.2654824463351$$
$$x_{25} = -25.1327415583355$$
$$x_{26} = 50.2654831903073$$
$$x_{27} = -56.5486674420455$$
$$x_{28} = 31.4159268773079$$
$$x_{29} = 87.9645950070109$$
$$x_{30} = -43.9822964797498$$
$$x_{31} = 62.8318538387145$$
$$x_{32} = -69.1150387179666$$
$$x_{33} = 94.2477789067916$$
$$x_{34} = 37.6991106584311$$
$$x_{35} = -50.2654813679338$$
$$x_{36} = -94.247780883276$$
$$x_{37} = -43.9822979612724$$
$$x_{38} = -87.9645943585376$$
$$x_{39} = 12.5663704380422$$
$$x_{40} = 6.28318459670391$$
$$x_{41} = 87.9645943359783$$
$$x_{42} = -31.4159277010283$$
$$x_{43} = -50.2654837025157$$
$$x_{44} = -69.1150376730368$$
$$x_{45} = 25.1327407479967$$
$$x_{46} = 100.530963886466$$
$$x_{47} = -37.6991125613034$$
$$x_{48} = -6.28318652181705$$
$$x_{49} = 100.530964756421$$
$$x_{50} = 43.9822962963654$$
$$x_{51} = 56.5486666937322$$
$$x_{52} = -50.2654822817914$$
$$x_{53} = -56.5486685086741$$
$$x_{54} = -37.699111070341$$
$$x_{55} = 94.2477796093522$$
$$x_{56} = -25.1327405036921$$
$$x_{57} = -12.5663713377117$$
$$x_{58} = -43.9822971745194$$
$$x_{59} = 94.2477803238238$$
$$x_{60} = 25.132741735205$$
$$x_{61} = 6.28318528418731$$
$$x_{62} = 43.9822978426937$$
$$x_{63} = 18.8495556012316$$
$$x_{64} = 69.1150379093021$$
$$x_{65} = -31.4159267211208$$
$$x_{66} = 56.5486675972206$$
$$x_{67} = 50.265481752718$$
$$x_{68} = 12.5663694979316$$
$$x_{69} = -81.6814081971126$$
$$x_{70} = -6.28318512226775$$
$$x_{71} = 12.5663718560491$$
$$x_{72} = -37.6991118773185$$
$$x_{73} = -18.8495554265332$$
$$x_{74} = 0$$
$$x_{75} = 69.1150388971777$$
$$x_{76} = -75.3982238802744$$
$$x_{77} = -94.2477794413798$$
$$x_{78} = -31.4159252975373$$
$$x_{79} = -94.2477785613568$$
$$x_{80} = 43.9822971694833$$
$$x_{81} = -75.3982249032445$$
$$x_{82} = -87.9645936379355$$