Hallemos los puntos de flexiones, para eso hay que resolver la ecuación
$$\frac{d^{2}}{d z^{2}} f{\left(z \right)} = 0$$
(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:
$$\frac{d^{2}}{d z^{2}} f{\left(z \right)} = $$
segunda derivada$$- \frac{\left(2 - \frac{2 z + \pi}{z}\right) \left(\frac{\left(2 - \frac{2 z + \pi}{z}\right) \sin{\left(\frac{z + \frac{\pi}{2}}{z} \right)}}{4} + \cos{\left(\frac{z + \frac{\pi}{2}}{z} \right)}\right)}{z^{2}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$z_{1} = 39593.458738055$$
$$z_{2} = -17257.5935852883$$
$$z_{3} = -29108.530995219$$
$$z_{4} = 17585.5403439427$$
$$z_{5} = 15896.5859631139$$
$$z_{6} = -34190.6211306688$$
$$z_{7} = -33343.5354513907$$
$$z_{8} = -32496.4752558919$$
$$z_{9} = 4.11152838284716$$
$$z_{10} = 28583.2945767901$$
$$z_{11} = 20966.8322839133$$
$$z_{12} = 35358.0984366944$$
$$z_{13} = -28261.6315265271$$
$$z_{14} = -38426.3756701413$$
$$z_{15} = -40120.8051810344$$
$$z_{16} = -35037.7305436374$$
$$z_{17} = -22334.7110333409$$
$$z_{18} = -16411.8654629508$$
$$z_{19} = 37052.1651061475$$
$$z_{20} = 26890.1095803329$$
$$z_{21} = -25721.1918358699$$
$$z_{22} = 29429.9812945101$$
$$z_{23} = 24350.9110867634$$
$$z_{24} = 41287.764026154$$
$$z_{25} = 25197.2220284511$$
$$z_{26} = -35884.8620969149$$
$$z_{27} = -23181.2317752336$$
$$z_{28} = -31649.4424707255$$
$$z_{29} = 37899.2390011097$$
$$z_{30} = 11684.0051854502$$
$$z_{31} = -13875.8878703664$$
$$z_{32} = 32817.2348357047$$
$$z_{33} = -14720.9818607812$$
$$z_{34} = 20121.1863278703$$
$$z_{35} = 23504.7027639242$$
$$z_{36} = 30276.7232572488$$
$$z_{37} = 31970.3540854403$$
$$z_{38} = -21488.2685826573$$
$$z_{39} = 21812.6470884737$$
$$z_{40} = 15052.7270449618$$
$$z_{41} = -26567.9581052107$$
$$z_{42} = -18103.4802804307$$
$$z_{43} = -29955.4678605162$$
$$z_{44} = 33664.1544606289$$
$$z_{45} = -20641.9132341026$$
$$z_{46} = -18949.5062407138$$
$$z_{47} = -39273.5824284916$$
$$z_{48} = -19795.6551734614$$
$$z_{49} = 12524.8461893486$$
$$z_{50} = -13031.0783983467$$
$$z_{51} = -40968.0429812156$$
$$z_{52} = -24027.8231477378$$
$$z_{53} = -41815.2949557426$$
$$z_{54} = 42982.1442199685$$
$$z_{55} = 18430.5066536153$$
$$z_{56} = 26043.6246675969$$
$$z_{57} = 40440.6013977027$$
$$z_{58} = 22658.6097888625$$
$$z_{59} = 14209.3969079262$$
$$z_{60} = -27414.7726898775$$
$$z_{61} = 34511.1099078989$$
$$z_{62} = -15566.3189683686$$
$$z_{63} = 36205.1175789306$$
$$z_{64} = 42134.9453547176$$
$$z_{65} = -12186.6048345281$$
$$z_{66} = 31123.5156192088$$
$$z_{67} = -37579.1859336477$$
$$z_{68} = -36732.0143366658$$
$$z_{69} = -11342.5317715139$$
$$z_{70} = -24874.4784586766$$
$$z_{71} = 16740.8811026829$$
$$z_{72} = -30802.4392217346$$
$$z_{73} = 27736.6685920197$$
$$z_{74} = 19275.7343319158$$
$$z_{75} = 38746.3374333537$$
$$z_{76} = 13366.7163652133$$
Además hay que calcular los límites de y'' para los argumentos tendientes a los puntos de indeterminación de la función:
Puntos donde hay indeterminación:
$$z_{1} = 0$$
True
True
- los límites no son iguales, signo
$$z_{1} = 0$$
- es el punto de flexión
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
$$\left[4.11152838284716, \infty\right)$$
Convexa en los intervalos
$$\left(-\infty, 4.11152838284716\right]$$