Hallemos los puntos de flexiones, para eso hay que resolver la ecuación
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0$$
(la segunda derivada es igual a cero),
las raíces de la ecuación obtenida serán los puntos de flexión para el gráfico de la función indicado:
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = $$
segunda derivada$$2 \left(3 x^{2} \left(\tan^{2}{\left(x \right)} + 1\right) + 3 x \tan{\left(x \right)} + \left(x^{3} + 4\right) \left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}\right) = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 31.3207337085427$$
$$x_{2} = 18.691809003885$$
$$x_{3} = 50.2058718640859$$
$$x_{4} = -28.1686058440378$$
$$x_{5} = 62.7841435647935$$
$$x_{6} = 2.48461039011352$$
$$x_{7} = 40.7673841393951$$
$$x_{8} = -69.0716591716208$$
$$x_{9} = 21.8556132276471$$
$$x_{10} = 69.0716602233947$$
$$x_{11} = -100.501132096352$$
$$x_{12} = 47.0603159403079$$
$$x_{13} = -65.9280035333118$$
$$x_{14} = -59.640042236382$$
$$x_{15} = 56.4956669310095$$
$$x_{16} = -75.3584555451937$$
$$x_{17} = 97.3585779468624$$
$$x_{18} = -62.784142024889$$
$$x_{19} = 59.6400441269827$$
$$x_{20} = -18.6916187878568$$
$$x_{21} = 91.0732704087587$$
$$x_{22} = -31.320709068384$$
$$x_{23} = -43.9141900064125$$
$$x_{24} = -78.5016373896593$$
$$x_{25} = -72.2151357298745$$
$$x_{26} = -5.82774384096051$$
$$x_{27} = 15.5194208026972$$
$$x_{28} = 43.9141964201018$$
$$x_{29} = -9.11476902458686$$
$$x_{30} = 94.2159595115209$$
$$x_{31} = -87.9305026777509$$
$$x_{32} = 87.9305030785993$$
$$x_{33} = -53.3509602105693$$
$$x_{34} = 53.3509631605549$$
$$x_{35} = 75.3584562878156$$
$$x_{36} = 9.1178357254917$$
$$x_{37} = 65.9280048001939$$
$$x_{38} = 100.501132331322$$
$$x_{39} = -15.5190261420429$$
$$x_{40} = -25.0139044407929$$
$$x_{41} = 78.5016380204025$$
$$x_{42} = -56.4956645839463$$
$$x_{43} = -94.2159592073433$$
$$x_{44} = 12.3324290989345$$
$$x_{45} = 25.0139646037045$$
$$x_{46} = -40.7673755125995$$
$$x_{47} = -34.4709155461949$$
$$x_{48} = 5.84372331689625$$
$$x_{49} = -50.2058681045286$$
$$x_{50} = 34.4709323753665$$
$$x_{51} = -97.358577680075$$
$$x_{52} = -91.0732700604052$$
$$x_{53} = 84.787648843337$$
$$x_{54} = -84.7876483797222$$
$$x_{55} = -37.6196954213083$$
$$x_{56} = 37.6197073036526$$
$$x_{57} = 81.6446976931462$$
$$x_{58} = -21.8555105796806$$
$$x_{59} = -81.6446971539845$$
$$x_{60} = 0$$
$$x_{61} = 72.2151366103182$$
$$x_{62} = 28.1686434009589$$
$$x_{63} = -12.3314640569818$$
$$x_{64} = -47.0603110734012$$
Intervalos de convexidad y concavidad:Hallemos los intervales donde la función es convexa o cóncava, para eso veamos cómo se comporta la función en los puntos de flexiones:
Cóncava en los intervalos
$$\left[100.501132331322, \infty\right)$$
Convexa en los intervalos
$$\left[-5.82774384096051, 0\right]$$