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$$\frac{\left(\frac{\left(1 - \frac{e^{\sin{\left(x \right)}}}{e^{\sin{\left(x \right)}} + 1}\right)^{2} \cos^{2}{\left(x \right)}}{4} - \frac{\left(1 - \frac{e^{\sin{\left(x \right)}}}{e^{\sin{\left(x \right)}} + 1}\right) \cos^{2}{\left(x \right)}}{2} + \frac{\left(1 - \frac{e^{\sin{\left(x \right)}}}{e^{\sin{\left(x \right)}} + 1}\right) e^{\sin{\left(x \right)}} \cos^{2}{\left(x \right)}}{2 \left(e^{\sin{\left(x \right)}} + 1\right)} - \frac{\sin{\left(x \right)}}{2} + \frac{\cos^{2}{\left(x \right)}}{2} + \frac{e^{\sin{\left(x \right)}} \sin{\left(x \right)}}{2 \left(e^{\sin{\left(x \right)}} + 1\right)} - \frac{3 e^{\sin{\left(x \right)}} \cos^{2}{\left(x \right)}}{2 \left(e^{\sin{\left(x \right)}} + 1\right)} + \frac{e^{2 \sin{\left(x \right)}} \cos^{2}{\left(x \right)}}{\left(e^{\sin{\left(x \right)}} + 1\right)^{2}}\right) e^{\frac{\sin{\left(x \right)}}{2}}}{\sqrt{e^{\sin{\left(x \right)}} + 1}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 72.4353095093614$$
$$x_{2} = 9.60345643756559$$
$$x_{3} = 6.10450683038338$$
$$x_{4} = -78.3611378629486$$
$$x_{5} = 59.8689388950023$$
$$x_{6} = 68.9363599021792$$
$$x_{7} = 87.785915823718$$
$$x_{8} = -21.8124700983323$$
$$x_{9} = -40.6620260198711$$
$$x_{10} = -34.3788407126915$$
$$x_{11} = 22.1698270519248$$
$$x_{12} = -2.96291417679359$$
$$x_{13} = -65.7947672485895$$
$$x_{14} = 97.5680507380798$$
$$x_{15} = 24.9540627519221$$
$$x_{16} = 91.2848654309002$$
$$x_{17} = -6.46186378397579$$
$$x_{18} = -44.1609756270533$$
$$x_{19} = 12.387692137563$$
$$x_{20} = -25.3114197055146$$
$$x_{21} = 41.0193829734635$$
$$x_{22} = -46.9452113270507$$
$$x_{23} = -9.24609948397317$$
$$x_{24} = -72.077952555769$$
$$x_{25} = -19.028234398335$$
$$x_{26} = 81.5027305165384$$
$$x_{27} = -0.178678476796208$$
$$x_{28} = 75.2195452093588$$
$$x_{29} = -88.1432727773104$$
$$x_{30} = -53.2283966342303$$
$$x_{31} = 31.2372480591017$$
$$x_{32} = 47.3025682806431$$
$$x_{33} = 175.750510124232$$
$$x_{34} = 3.320271130386$$
$$x_{35} = -97.2106937844874$$
$$x_{36} = -84.6443231701282$$
$$x_{37} = -63.0105315485921$$
$$x_{38} = -94.42645808449$$
$$x_{39} = 556.24057816219$$
$$x_{40} = 78.718494816541$$
$$x_{41} = 66.1521242021819$$
$$x_{42} = 43.8036186734609$$
$$x_{43} = -50.4441609342329$$
$$x_{44} = -31.5946050126941$$
$$x_{45} = 94.0691011308976$$
$$x_{46} = -37.8777903198737$$
$$x_{47} = -75.5769021629512$$
$$x_{48} = 56.3699892878201$$
$$x_{49} = -81.8600874701308$$
$$x_{50} = 50.0868039806405$$
$$x_{51} = 62.6531745949997$$
$$x_{52} = 100.352286438077$$
$$x_{53} = 34.7361976662839$$
$$x_{54} = 37.5204333662813$$
$$x_{55} = -59.5115819414099$$
$$x_{56} = 18.6708774447426$$
$$x_{57} = -69.2937168557717$$
$$x_{58} = 28.4530123591043$$
$$x_{59} = -28.0956554055119$$
$$x_{60} = 53.5857535878227$$
$$x_{61} = -15.5292847911528$$
$$x_{62} = 15.8866417447452$$
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
$$\left[556.24057816219, \infty\right)$$
Convexa en los intervalos
$$\left(-\infty, -97.2106937844874\right]$$