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$$- \frac{2 \sin{\left(\frac{1}{x} \right)} + \frac{\cos{\left(\frac{1}{x} \right)}}{x}}{x^{3}} = 0$$
Solve this equationThe roots of this equation
$$x_{1} = 2852.18048814786$$
$$x_{2} = 10920.4961326302$$
$$x_{3} = -8487.98297415597$$
$$x_{4} = -3690.60517565222$$
$$x_{5} = -7397.65078485226$$
$$x_{6} = 10702.4279394484$$
$$x_{7} = 9830.15607053174$$
$$x_{8} = 4596.59700962761$$
$$x_{9} = -4562.82951485885$$
$$x_{10} = 10484.3598310079$$
$$x_{11} = 8085.61819208994$$
$$x_{12} = 7649.4854303998$$
$$x_{13} = -9142.18445899447$$
$$x_{14} = 1980.06831995953$$
$$x_{15} = 5032.71688419619$$
$$x_{16} = 7213.35359972748$$
$$x_{17} = 6559.15800566404$$
$$x_{18} = -2164.32241907986$$
$$x_{19} = 5904.96575692001$$
$$x_{20} = 1762.06641001527$$
$$x_{21} = -4998.94909118433$$
$$x_{22} = -1510.33069137687$$
$$x_{23} = -5871.19755389099$$
$$x_{24} = 7867.55170454519$$
$$x_{25} = -8706.04998202671$$
$$x_{26} = -6307.32515246242$$
$$x_{27} = -8269.91613624535$$
$$x_{28} = -3908.6588920217$$
$$x_{29} = 6123.0294019367$$
$$x_{30} = -8924.11714739678$$
$$x_{31} = -4344.77129946241$$
$$x_{32} = -3254.50438518975$$
$$x_{33} = -2382.34641253713$$
$$x_{34} = 9612.08836001311$$
$$x_{35} = -9360.25190659859$$
$$x_{36} = 10048.2238904202$$
$$x_{37} = -3036.45826575513$$
$$x_{38} = -7615.71678829324$$
$$x_{39} = 4814.65648065893$$
$$x_{40} = -8051.84948210571$$
$$x_{41} = -10232.5228831544$$
$$x_{42} = 4160.48145172456$$
$$x_{43} = -1728.30948622997$$
$$x_{44} = -3472.55353426121$$
$$x_{45} = 5468.84004252579$$
$$x_{46} = 6341.09349991192$$
$$x_{47} = 10266.2918127088$$
$$x_{48} = -6525.38959659195$$
$$x_{49} = 2634.14196282981$$
$$x_{50} = -10014.4549765932$$
$$x_{51} = -5217.01018907647$$
$$x_{52} = 8739.81877537654$$
$$x_{53} = 2416.10916381092$$
$$x_{54} = -7179.58503821156$$
$$x_{55} = 6777.22287982727$$
$$x_{56} = 3506.31973323777$$
$$x_{57} = -5653.13449897004$$
$$x_{58} = -10886.7271614234$$
$$x_{59} = -1292.38283163016$$
$$x_{60} = -4780.88882660632$$
$$x_{61} = 7431.41938844086$$
$$x_{62} = -2600.37816709516$$
$$x_{63} = 3724.37172736816$$
$$x_{64} = 1544.08382506109$$
$$x_{65} = 1326.13012084789$$
$$x_{66} = -2818.4158797084$$
$$x_{67} = 6995.28808794494$$
$$x_{68} = -10450.5908866988$$
$$x_{69} = -9578.31948091886$$
$$x_{70} = -5435.0720199532$$
$$x_{71} = -6961.51957250769$$
$$x_{72} = 8521.75174184478$$
$$x_{73} = 4378.53861045658$$
$$x_{74} = -10668.6589812788$$
$$x_{75} = 5250.77810403946$$
$$x_{76} = 9394.02076648111$$
$$x_{77} = -6089.26112283023$$
$$x_{78} = 9175.95329827666$$
$$x_{79} = 3942.42573932$$
$$x_{80} = 3070.22351896922$$
$$x_{81} = -1946.30879913818$$
$$x_{82} = -6743.45441499989$$
$$x_{83} = 8303.68487622058$$
$$x_{84} = -9796.38717349232$$
$$x_{85} = -7833.78302708594$$
$$x_{86} = -4126.71435428679$$
$$x_{87} = 3288.2701585224$$
$$x_{88} = 2198.08379682573$$
$$x_{89} = 8957.88596455289$$
$$x_{90} = 5686.90261697445$$
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