El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cos{\left(x - \frac{3}{10} \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \frac{3}{10} + \frac{\pi}{2}$$
$$x_{2} = \frac{3}{10} + \frac{3 \pi}{2}$$
Solución numérica$$x_{1} = -86.0937979737193$$
$$x_{2} = 96.1185759344887$$
$$x_{3} = 36.4283155162826$$
$$x_{4} = 83.5522053201295$$
$$x_{5} = -51.5362787842316$$
$$x_{6} = -76.6690200129499$$
$$x_{7} = 8.15398163397448$$
$$x_{8} = 89.8353906273091$$
$$x_{9} = 48.9946861306418$$
$$x_{10} = -32.6867228626928$$
$$x_{11} = 17.5787595947439$$
$$x_{12} = 45.853093477052$$
$$x_{13} = 64.7026493985908$$
$$x_{14} = -98.6601685880785$$
$$x_{15} = 1.8707963267949$$
$$x_{16} = 86.6937979737193$$
$$x_{17} = 121.251317163207$$
$$x_{18} = -7.55398163397448$$
$$x_{19} = -73.5274273593601$$
$$x_{20} = 1984.21576074195$$
$$x_{21} = 645.897290312702$$
$$x_{22} = -38.9699081698724$$
$$x_{23} = 14.4371669411541$$
$$x_{24} = 70.9858347057703$$
$$x_{25} = -35.8283155162826$$
$$x_{26} = -1.2707963267949$$
$$x_{27} = 80.4106126665397$$
$$x_{28} = -10.6955742875643$$
$$x_{29} = -67.2442420521806$$
$$x_{30} = -4.41238898038469$$
$$x_{31} = -92.3769832808989$$
$$x_{32} = 99.2601685880785$$
$$x_{33} = -814.943293606551$$
$$x_{34} = -54.6778714378214$$
$$x_{35} = -64.1026493985908$$
$$x_{36} = 58.4194640914112$$
$$x_{37} = -26.4035375555132$$
$$x_{38} = -57.8194640914112$$
$$x_{39} = -60.961056745001$$
$$x_{40} = 61.561056745001$$
$$x_{41} = 5.01238898038469$$
$$x_{42} = 92.9769832808989$$
$$x_{43} = 23.8619449019235$$
$$x_{44} = 20.7203522483337$$
$$x_{45} = 74.1274273593601$$
$$x_{46} = 67.8442420521806$$
$$x_{47} = -20.1203522483337$$
$$x_{48} = -3865.42976024224$$
$$x_{49} = 55.2778714378214$$
$$x_{50} = -70.3858347057703$$
$$x_{51} = 77.2690200129499$$
$$x_{52} = 30.145130209103$$
$$x_{53} = -29.545130209103$$
$$x_{54} = 11.2955742875643$$
$$x_{55} = -89.2353906273091$$
$$x_{56} = -95.5185759344887$$
$$x_{57} = -13.8371669411541$$
$$x_{58} = -16.9787595947439$$
$$x_{59} = -48.3946861306418$$
$$x_{60} = -42.1115008234622$$
$$x_{61} = 21151.0725402933$$
$$x_{62} = 52.1362787842316$$
$$x_{63} = -79.8106126665397$$
$$x_{64} = 27.0035375555132$$
$$x_{65} = 39.5699081698724$$
$$x_{66} = 42.7115008234622$$
$$x_{67} = -82.9522053201295$$
$$x_{68} = -45.253093477052$$
$$x_{69} = -23.2619449019234$$
$$x_{70} = 33.2867228626928$$