El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\frac{\tan{\left(x \right)}}{4} - 1 = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \operatorname{atan}{\left(4 \right)}$$
Solución numérica$$x_{1} = 13.8921882780272$$
$$x_{2} = -74.072406022487$$
$$x_{3} = -39.5148868329993$$
$$x_{4} = -52.0812574473585$$
$$x_{5} = -96.0635545976156$$
$$x_{6} = -23.8069235650503$$
$$x_{7} = 95.5735972713618$$
$$x_{8} = -45.7980721401789$$
$$x_{9} = 42.1665221603353$$
$$x_{10} = -89.780369290436$$
$$x_{11} = -1.81577498992176$$
$$x_{12} = -67.7892207153074$$
$$x_{13} = 57.8744854282843$$
$$x_{14} = 20.1753735852068$$
$$x_{15} = 7.60900297084762$$
$$x_{16} = -8.09896029710135$$
$$x_{17} = 92.432004617772$$
$$x_{18} = -36.3732941794095$$
$$x_{19} = -271.992743198644$$
$$x_{20} = 10.7505956244374$$
$$x_{21} = -30.0901088722299$$
$$x_{22} = -152.612222362232$$
$$x_{23} = 35.8833368531558$$
$$x_{24} = 86.1488193105924$$
$$x_{25} = 64.1576707354639$$