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$$- \frac{\sin{\left(x \right)} \cos{\left(\frac{\sin{\left(x \right)}}{\pi} \right)} + \frac{\sin{\left(\frac{\sin{\left(x \right)}}{\pi} \right)} \cos^{2}{\left(x \right)}}{\pi}}{\pi} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 12.5663706143592$$
$$x_{2} = 53.4070751110265$$
$$x_{3} = -97.3893722612836$$
$$x_{4} = 37.6991118430775$$
$$x_{5} = 97.3893722612836$$
$$x_{6} = 78.5398163397448$$
$$x_{7} = -59.6902604182061$$
$$x_{8} = -65.9734457253857$$
$$x_{9} = 0$$
$$x_{10} = -31.4159265358979$$
$$x_{11} = -229.336263712055$$
$$x_{12} = -50.2654824574367$$
$$x_{13} = -21.9911485751286$$
$$x_{14} = 6.28318530717959$$
$$x_{15} = -34.5575191894877$$
$$x_{16} = -69.1150383789755$$
$$x_{17} = -94.2477796076938$$
$$x_{18} = -15.707963267949$$
$$x_{19} = 21.9911485751286$$
$$x_{20} = 69.1150383789755$$
$$x_{21} = 62.8318530717959$$
$$x_{22} = 50.2654824574367$$
$$x_{23} = 81.6814089933346$$
$$x_{24} = 100.530964914873$$
$$x_{25} = -40.8407044966673$$
$$x_{26} = 9.42477796076938$$
$$x_{27} = -87.9645943005142$$
$$x_{28} = 34.5575191894877$$
$$x_{29} = 65.9734457253857$$
$$x_{30} = -62.8318530717959$$
$$x_{31} = -18.8495559215388$$
$$x_{32} = -28.2743338823081$$
$$x_{33} = -497647.125884545$$
$$x_{34} = -56.5486677646163$$
$$x_{35} = -53.4070751110265$$
$$x_{36} = -37.6991118430775$$
$$x_{37} = -25.1327412287183$$
$$x_{38} = -100.530964914873$$
$$x_{39} = -9.42477796076938$$
$$x_{40} = 40.8407044966673$$
$$x_{41} = -91.106186954104$$
$$x_{42} = -75.398223686155$$
$$x_{43} = 18.8495559215388$$
$$x_{44} = 87.9645943005142$$
$$x_{45} = 59.6902604182061$$
$$x_{46} = 10313.8486817353$$
$$x_{47} = -6.28318530717959$$
$$x_{48} = 25.1327412287183$$
$$x_{49} = 47.1238898038469$$
$$x_{50} = 91.106186954104$$
$$x_{51} = 28.2743338823081$$
$$x_{52} = 56.5486677646163$$
$$x_{53} = -43.9822971502571$$
$$x_{54} = -47.1238898038469$$
$$x_{55} = -845.088423815654$$
$$x_{56} = 31.4159265358979$$
$$x_{57} = 94.2477796076938$$
$$x_{58} = -12.5663706143592$$
$$x_{59} = 75.398223686155$$
$$x_{60} = -3.14159265358979$$
$$x_{61} = -72.2566310325652$$
$$x_{62} = -84.8230016469244$$
$$x_{63} = 84.8230016469244$$
$$x_{64} = 72.2566310325652$$
$$x_{65} = -81.6814089933346$$
$$x_{66} = 43.9822971502571$$
$$x_{67} = -78.5398163397448$$
$$x_{68} = 15.707963267949$$
$$x_{69} = 3.14159265358979$$
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
$$\left[10313.8486817353, \infty\right)$$
Convexa en los intervalos
$$\left(-\infty, -845.088423815654\right]$$