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$$\frac{2 \left(- \frac{2 x \left(2 x^{2} + 1\right) \left(\tan^{2}{\left(x \right)} + 1\right)}{x^{4} + x^{2} + 5} + \left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)} - \frac{\left(- \frac{4 x^{2} \left(2 x^{2} + 1\right)^{2}}{x^{4} + x^{2} + 5} + 6 x^{2} + 1\right) \tan{\left(x \right)}}{x^{4} + x^{2} + 5}\right)}{x^{4} + x^{2} + 5} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -91.149987348733$$
$$x_{2} = 3.7608338874361$$
$$x_{3} = 62.8951983516334$$
$$x_{4} = -100.570675868524$$
$$x_{5} = -3.7608338874361$$
$$x_{6} = 47.2080273947305$$
$$x_{7} = -62.8951983516334$$
$$x_{8} = 22.1661280563682$$
$$x_{9} = -25.2871859346973$$
$$x_{10} = 19.0510630137868$$
$$x_{11} = 84.8700293777013$$
$$x_{12} = 69.172674560332$$
$$x_{13} = -34.6714063759229$$
$$x_{14} = 44.0723287767864$$
$$x_{15} = 59.7569040345638$$
$$x_{16} = -72.3117805427902$$
$$x_{17} = -47.2080273947305$$
$$x_{18} = -94.2901265771818$$
$$x_{19} = 15.9448518567147$$
$$x_{20} = 40.9375079301731$$
$$x_{21} = -15.9448518567147$$
$$x_{22} = 31.5407884465079$$
$$x_{23} = 100.570675868524$$
$$x_{24} = -44.0723287767864$$
$$x_{25} = -28.4124569255978$$
$$x_{26} = -69.172674560332$$
$$x_{27} = -53.4814577901855$$
$$x_{28} = -50.3444447520328$$
$$x_{29} = 0$$
$$x_{30} = -40.9375079301731$$
$$x_{31} = 50.3444447520328$$
$$x_{32} = 75.4510915111814$$
$$x_{33} = -88.0099511717168$$
$$x_{34} = 53.4814577901855$$
$$x_{35} = -78.590583200109$$
$$x_{36} = 37.8037738409624$$
$$x_{37} = 25.2871859346973$$
$$x_{38} = 6.74671474060891$$
$$x_{39} = 91.149987348733$$
$$x_{40} = -6.74671474060891$$
$$x_{41} = 97.4303589713879$$
$$x_{42} = 9.7816361116334$$
$$x_{43} = 94.2901265771818$$
$$x_{44} = -75.4510915111814$$
$$x_{45} = -12.852286570046$$
$$x_{46} = 28.4124569255978$$
$$x_{47} = -9.7816361116334$$
$$x_{48} = -84.8700293777013$$
$$x_{49} = -81.7302350177074$$
$$x_{50} = 56.6189698595128$$
$$x_{51} = 81.7302350177074$$
$$x_{52} = -66.0338023562199$$
$$x_{53} = 72.3117805427902$$
$$x_{54} = 66.0338023562199$$
$$x_{55} = -59.7569040345638$$
$$x_{56} = 12.852286570046$$
$$x_{57} = -22.1661280563682$$
$$x_{58} = 88.0099511717168$$
$$x_{59} = 78.590583200109$$
$$x_{60} = -56.6189698595128$$
$$x_{61} = 34.6714063759229$$
$$x_{62} = -19.0510630137868$$
$$x_{63} = -31.5407884465079$$
$$x_{64} = -37.8037738409624$$
$$x_{65} = -97.4303589713879$$
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
$$\left[100.570675868524, \infty\right)$$
Convexa en los intervalos
$$\left(-\infty, -100.570675868524\right]$$