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$$\left(- \sin{\left(x \right)} + 2 \cos^{2}{\left(x \right)} \tan{\left(\sin{\left(x \right)} \right)}\right) \left(\tan^{2}{\left(\sin{\left(x \right)} \right)} + 1\right) = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 65.9734457253857$$
$$x_{2} = -54.2984478147474$$
$$x_{3} = 48.0152625075678$$
$$x_{4} = -21.9911485751286$$
$$x_{5} = 21.9911485751286$$
$$x_{6} = 96.4979995575627$$
$$x_{7} = -15.707963267949$$
$$x_{8} = -4.03296535731068$$
$$x_{9} = -11.6749979106383$$
$$x_{10} = 97.3893722612836$$
$$x_{11} = -24.2413685249975$$
$$x_{12} = -61.940480368075$$
$$x_{13} = -76.2895963898759$$
$$x_{14} = 6.28318530717959$$
$$x_{15} = 68.2236656752546$$
$$x_{16} = 7.17455801090047$$
$$x_{17} = 41.7320772003882$$
$$x_{18} = 28.2743338823081$$
$$x_{19} = -94.2477796076938$$
$$x_{20} = -12.5663706143592$$
$$x_{21} = -83.9316289432035$$
$$x_{22} = 17.9581832178179$$
$$x_{23} = -70.0064110826963$$
$$x_{24} = 85.7143743506453$$
$$x_{25} = 10.3161506644903$$
$$x_{26} = -53.4070751110265$$
$$x_{27} = -39.9493317929464$$
$$x_{28} = -90.2148142503831$$
$$x_{29} = -33.6661464857668$$
$$x_{30} = 90.2148142503831$$
$$x_{31} = 59.6902604182061$$
$$x_{32} = 32.3072992396188$$
$$x_{33} = -79.4311890434657$$
$$x_{34} = -91.9975596578249$$
$$x_{35} = 56.5486677646163$$
$$x_{36} = 26.0241139324392$$
$$x_{37} = -2.25021994986891$$
$$x_{38} = 72.2566310325652$$
$$x_{39} = -50.2654824574367$$
$$x_{40} = -26.0241139324392$$
$$x_{41} = 78.5398163397448$$
$$x_{42} = 61.940480368075$$
$$x_{43} = -87.9645943005142$$
$$x_{44} = 37.6991118430775$$
$$x_{45} = -6.28318530717959$$
$$x_{46} = -13.4577433180801$$
$$x_{47} = -37.6991118430775$$
$$x_{48} = -43.9822971502571$$
$$x_{49} = -48.0152625075678$$
$$x_{50} = 74.5068509824341$$
$$x_{51} = 24.2413685249975$$
$$x_{52} = 63.7232257755168$$
$$x_{53} = 70.0064110826963$$
$$x_{54} = 19.7409286252596$$
$$x_{55} = -41.7320772003882$$
$$x_{56} = -72.2566310325652$$
$$x_{57} = -81.6814089933346$$
$$x_{58} = 98.2807449650045$$
$$x_{59} = -65.9734457253857$$
$$x_{60} = -85.7143743506453$$
$$x_{61} = 0$$
$$x_{62} = -17.9581832178179$$
$$x_{63} = -63.7232257755168$$
$$x_{64} = 2.25021994986891$$
$$x_{65} = -28.2743338823081$$
$$x_{66} = -19.7409286252596$$
$$x_{67} = -68.2236656752546$$
$$x_{68} = 43.9822971502571$$
$$x_{69} = 8.53340525704849$$
$$x_{70} = 100.530964914873$$
$$x_{71} = -97.3893722612836$$
$$x_{72} = -35.4488918932086$$
$$x_{73} = 81.6814089933346$$
$$x_{74} = -75.398223686155$$
$$x_{75} = 4.03296535731068$$
$$x_{76} = -57.4400404683372$$
$$x_{77} = -77.6484436360239$$
$$x_{78} = 50.2654824574367$$
$$x_{79} = 94.2477796076938$$
$$x_{80} = -59.6902604182061$$
$$x_{81} = 12.5663706143592$$
$$x_{82} = 52.5157024073056$$
$$x_{83} = 46.232517100126$$
$$x_{84} = 34.5575191894877$$
$$x_{85} = 39.9493317929464$$
$$x_{86} = 30.524553832177$$
$$x_{87} = 15.707963267949$$
$$x_{88} = 87.9645943005142$$
$$x_{89} = -99.6395922111525$$
$$x_{90} = 76.2895963898759$$
$$x_{91} = 83.9316289432035$$
$$x_{92} = -9.42477796076938$$
$$x_{93} = -55.6572950608954$$
$$x_{94} = -46.232517100126$$
$$x_{95} = 54.2984478147474$$
$$x_{96} = -31.4159265358979$$
$$x_{97} = 75.398223686155$$
$$x_{98} = 91.9975596578249$$
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
$$\left[100.530964914873, \infty\right)$$
Convexa en los intervalos
$$\left(-\infty, -94.2477796076938\right]$$