Let's find the inflection points, we'll need to solve the equation for this
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0$$
(the second derivative equals zero),
the roots of this equation will be the inflection points for the specified function graph:
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = $$
the second derivative$$- \frac{\pi \left(12 \sin{\left(\frac{\pi}{6 x} \right)} + \frac{\pi \cos{\left(\frac{\pi}{6 x} \right)}}{x}\right)}{36 x^{3}} = 0$$
Solve this equationThe roots of this equation
$$x_{1} = -2818.17985032454$$
$$x_{2} = 6340.98861933592$$
$$x_{3} = 1325.62783396218$$
$$x_{4} = -4344.61821963262$$
$$x_{5} = -7397.56088668859$$
$$x_{6} = 7867.46717504615$$
$$x_{7} = -7615.62946448072$$
$$x_{8} = 7431.32989758148$$
$$x_{9} = 2633.88939928703$$
$$x_{10} = -5434.94965493664$$
$$x_{11} = -3908.48872641532$$
$$x_{12} = 8739.74268294699$$
$$x_{13} = -4562.68375267685$$
$$x_{14} = 10266.227035013$$
$$x_{15} = -3472.36198908238$$
$$x_{16} = -10014.3885704922$$
$$x_{17} = -10886.6660761859$$
$$x_{18} = -1291.86742616671$$
$$x_{19} = -10232.4578923205$$
$$x_{20} = 3070.00685227131$$
$$x_{21} = 3288.06786705394$$
$$x_{22} = -7833.69813428534$$
$$x_{23} = -9360.18085900573$$
$$x_{24} = -6525.28768017201$$
$$x_{25} = -5216.88270843295$$
$$x_{26} = 5686.78566939941$$
$$x_{27} = -4998.8160484904$$
$$x_{28} = -3036.23919565166$$
$$x_{29} = 1979.73222026469$$
$$x_{30} = 5250.65144091284$$
$$x_{31} = 8085.53594253715$$
$$x_{32} = -5871.08427988076$$
$$x_{33} = 10702.3658016624$$
$$x_{34} = -10668.5966473995$$
$$x_{35} = -4126.55318316551$$
$$x_{36} = 9612.0191732323$$
$$x_{37} = -7179.49240929446$$
$$x_{38} = 4596.45231528642$$
$$x_{39} = 8521.67370209041$$
$$x_{40} = 1761.68865570757$$
$$x_{41} = 9830.0884186573$$
$$x_{42} = 7649.39849094743$$
$$x_{43} = -1509.889858162$$
$$x_{44} = 2197.78107473499$$
$$x_{45} = 2851.94724640043$$
$$x_{46} = -9796.31928911212$$
$$x_{47} = 5032.58473166839$$
$$x_{48} = 6777.12474945546$$
$$x_{49} = 4160.32158515819$$
$$x_{50} = 10920.4352357204$$
$$x_{51} = -1727.92436279509$$
$$x_{52} = -6961.42404173471$$
$$x_{53} = -6089.15190588714$$
$$x_{54} = 3724.19313358569$$
$$x_{55} = -10450.5272520647$$
$$x_{56} = -3690.42495217852$$
$$x_{57} = 6122.92078558727$$
$$x_{58} = 1107.62093043542$$
$$x_{59} = -8269.83572081291$$
$$x_{60} = 9393.94997352679$$
$$x_{61} = -4780.74971433103$$
$$x_{62} = 5468.71843092131$$
$$x_{63} = 2415.83378705527$$
$$x_{64} = -8051.76688862548$$
$$x_{65} = 4814.51834133231$$
$$x_{66} = 6559.05661241827$$
$$x_{67} = 8303.60478685093$$
$$x_{68} = 3942.25702729704$$
$$x_{69} = -8924.04262738392$$
$$x_{70} = 8957.81172462897$$
$$x_{71} = 4378.38670795195$$
$$x_{72} = 5904.85312882267$$
$$x_{73} = 7213.26140317638$$
$$x_{74} = -8487.90462484683$$
$$x_{75} = -6743.35579466655$$
$$x_{76} = 1543.6526220021$$
$$x_{77} = -5653.0168548326$$
$$x_{78} = -1073.864430426$$
$$x_{79} = -2600.12233157429$$
$$x_{80} = -9578.25005094313$$
$$x_{81} = 3506.13002791958$$
$$x_{82} = 10048.1577068254$$
$$x_{83} = -6307.2197120043$$
$$x_{84} = 9175.88082280012$$
$$x_{85} = -3254.3000002424$$
$$x_{86} = -2382.06714128044$$
$$x_{87} = -8705.97359532772$$
$$x_{88} = -1945.96687906663$$
$$x_{89} = -2164.01498372506$$
$$x_{90} = -9142.11171660862$$
$$x_{91} = 10484.2964007232$$
$$x_{92} = 6995.19301698607$$
You also need to calculate the limits of y '' for arguments seeking to indeterminate points of a function:
Points where there is an indetermination:
$$x_{1} = 0$$
True
True
- the limits are not equal, so
$$x_{1} = 0$$
- is an inflection point
Сonvexity and concavity intervals:Let’s find the intervals where the function is convex or concave, for this look at the behaviour of the function at the inflection points:
Have no bends at the whole real axis