El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\left(\cos{\left(x \right)} + 2\right) \sin{\left(2 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
Solución numérica$$x_{1} = -144.51326206513$$
$$x_{2} = -59.6902604182061$$
$$x_{3} = 7.85398163397448$$
$$x_{4} = -21.9911485751286$$
$$x_{5} = -75.398223686155$$
$$x_{6} = 50.2654824574367$$
$$x_{7} = 95.8185759344887$$
$$x_{8} = 34.5575191894877$$
$$x_{9} = -86.3937979737193$$
$$x_{10} = -45.553093477052$$
$$x_{11} = 26.7035375555132$$
$$x_{12} = -114.668131856027$$
$$x_{13} = -20.4203522483337$$
$$x_{14} = 0$$
$$x_{15} = -34.5575191894877$$
$$x_{16} = -64.4026493985908$$
$$x_{17} = 43.9822971502571$$
$$x_{18} = -43.9822971502571$$
$$x_{19} = 97.3893722612836$$
$$x_{20} = -58.1194640914112$$
$$x_{21} = 84.8230016469244$$
$$x_{22} = 23.5619449019235$$
$$x_{23} = -80.1106126665397$$
$$x_{24} = -65.9734457253857$$
$$x_{25} = 86.3937979737193$$
$$x_{26} = 56.5486677646163$$
$$x_{27} = 51.8362787842316$$
$$x_{28} = 40.8407044966673$$
$$x_{29} = -87.9645943005142$$
$$x_{30} = 47.1238898038469$$
$$x_{31} = -14.1371669411541$$
$$x_{32} = 53.4070751110265$$
$$x_{33} = 20.4203522483337$$
$$x_{34} = 87.9645943005142$$
$$x_{35} = 59.6902604182061$$
$$x_{36} = -73.8274273593601$$
$$x_{37} = -81.6814089933346$$
$$x_{38} = 72.2566310325652$$
$$x_{39} = -9.42477796076938$$
$$x_{40} = -76.9690200129499$$
$$x_{41} = -29.845130209103$$
$$x_{42} = 675.442420521806$$
$$x_{43} = -72.2566310325652$$
$$x_{44} = 81.6814089933346$$
$$x_{45} = -31.4159265358979$$
$$x_{46} = -89.5353906273091$$
$$x_{47} = 64.4026493985908$$
$$x_{48} = 9.42477796076938$$
$$x_{49} = 3.14159265358979$$
$$x_{50} = -94.2477796076938$$
$$x_{51} = -50.2654824574367$$
$$x_{52} = 28.2743338823081$$
$$x_{53} = 38588.1825640434$$
$$x_{54} = 29.845130209103$$
$$x_{55} = -51.8362787842316$$
$$x_{56} = -67.5442420521806$$
$$x_{57} = 100.530964914873$$
$$x_{58} = -3.14159265358979$$
$$x_{59} = -53.4070751110265$$
$$x_{60} = 94.2477796076938$$
$$x_{61} = 21.9911485751286$$
$$x_{62} = -36.1283155162826$$
$$x_{63} = -15.707963267949$$
$$x_{64} = -7.85398163397448$$
$$x_{65} = 65.9734457253857$$
$$x_{66} = 14.1371669411541$$
$$x_{67} = -6.28318530717959$$
$$x_{68} = 80.1106126665397$$
$$x_{69} = 78.5398163397448$$
$$x_{70} = 15.707963267949$$
$$x_{71} = 37.6991118430775$$
$$x_{72} = 42.4115008234622$$
$$x_{73} = -97.3893722612836$$
$$x_{74} = -78.5398163397448$$
$$x_{75} = 70.6858347057703$$
$$x_{76} = 36.1283155162826$$
$$x_{77} = -1.5707963267949$$
$$x_{78} = -95.8185759344887$$
$$x_{79} = 6.28318530717959$$
$$x_{80} = -23.5619449019235$$
$$x_{81} = -28.2743338823081$$
$$x_{82} = -40.8407044966673$$
$$x_{83} = -91.106186954104$$
$$x_{84} = 67.5442420521806$$
$$x_{85} = 12.5663706143592$$
$$x_{86} = -17.2787595947439$$
$$x_{87} = -37.6991118430775$$
$$x_{88} = 595.331807855266$$
$$x_{89} = 73.8274273593601$$
$$x_{90} = 58.1194640914112$$
$$x_{91} = -61.261056745001$$
$$x_{92} = -47.1238898038469$$