El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cos{\left(x - \frac{\pi}{4} \right)} + 1 = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{3 \pi}{4}$$
$$x_{2} = \frac{5 \pi}{4}$$
Solución numérica$$x_{1} = 85.6084000399172$$
$$x_{2} = -96.603974564695$$
$$x_{3} = 29.0597324769089$$
$$x_{4} = -46.3384921486845$$
$$x_{5} = 60.4756584532596$$
$$x_{6} = 60.4756586345947$$
$$x_{7} = -96.6039737800289$$
$$x_{8} = -21.2057499200041$$
$$x_{9} = -65.188047073324$$
$$x_{10} = 91.8915853225807$$
$$x_{11} = 47.909287468617$$
$$x_{12} = -84.0376034462788$$
$$x_{13} = -13404.3904536702$$
$$x_{14} = -90.3207892979081$$
$$x_{15} = -33.7721210086069$$
$$x_{16} = 3.92699032122665$$
$$x_{17} = 29.0597316738462$$
$$x_{18} = 54.1924733268324$$
$$x_{19} = -115.453529926716$$
$$x_{20} = -27.4889355511657$$
$$x_{21} = 98.1747708802112$$
$$x_{22} = 91.8915846163827$$
$$x_{23} = 47.9092881995972$$
$$x_{24} = 85.6083989845666$$
$$x_{25} = -71.4712326353295$$
$$x_{26} = -90.3207892086502$$
$$x_{27} = 98.1747700238345$$
$$x_{28} = 98.1747705007628$$
$$x_{29} = -71.4712330231824$$
$$x_{30} = -65.1880478408216$$
$$x_{31} = 35.3429168981644$$
$$x_{32} = -2.35619509671576$$
$$x_{33} = 16.4933619477574$$
$$x_{34} = -77.7544176954284$$
$$x_{35} = -46.338492146518$$
$$x_{36} = -90.320788593313$$
$$x_{37} = 66.7588444068268$$
$$x_{38} = -40.0553062819826$$
$$x_{39} = -71.4712323525471$$
$$x_{40} = 10.210175749086$$
$$x_{41} = -46.3384914348609$$
$$x_{42} = 35.3429180284231$$
$$x_{43} = -58.9048618338034$$
$$x_{44} = -27.4889352022727$$
$$x_{45} = 66.758843631929$$
$$x_{46} = 79.3252140527191$$
$$x_{47} = -33.7721205506926$$
$$x_{48} = 54.1924728859244$$
$$x_{49} = 73.0420296320937$$
$$x_{50} = -33.7721213865886$$
$$x_{51} = 66.7588443861661$$
$$x_{52} = -77.7544185209968$$
$$x_{53} = 73.0420288301818$$
$$x_{54} = 79.3252143781653$$
$$x_{55} = 10.210176157677$$
$$x_{56} = -14.9225646783909$$
$$x_{57} = -2.35619427650782$$
$$x_{58} = -33.7721219065776$$
$$x_{59} = -21.2057506833124$$
$$x_{60} = -27.4889358644641$$
$$x_{61} = 79.3252148477219$$
$$x_{62} = 16.4933615389937$$
$$x_{63} = -40.0553060529486$$
$$x_{64} = 3.92699088103501$$
$$x_{65} = -2.35619499491606$$
$$x_{66} = -77.7544181730285$$
$$x_{67} = 41.6261028817504$$
$$x_{68} = 54.1924737371634$$
$$x_{69} = 41.6261021568912$$
$$x_{70} = -14.9225654823937$$
$$x_{71} = -8.63938025625821$$
$$x_{72} = 35.342917690916$$
$$x_{73} = -8.63937946597846$$
$$x_{74} = -84.0376031821128$$
$$x_{75} = 91.8915852045393$$
$$x_{76} = 47.9092880431314$$
$$x_{77} = 22.7765472331605$$
$$x_{78} = 60.475659097534$$
$$x_{79} = -52.6216766229604$$
$$x_{80} = 85.6083993088973$$
$$x_{81} = -40.0553068257685$$
$$x_{82} = 10.2101765935161$$
$$x_{83} = 16.4933612943477$$
$$x_{84} = -84.0376039723467$$
$$x_{85} = 41.6261019474067$$
$$x_{86} = 22.7765464742714$$
$$x_{87} = 3.92699107435062$$
$$x_{88} = -52.6216774105457$$
$$x_{89} = -58.9048626385362$$