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$$- \frac{2 \cdot \left(3 + \frac{2}{x^{2} \cdot \left(1 - \frac{1}{x^{2}}\right)}\right)}{x^{4} \cdot \left(1 - \frac{1}{x^{2}}\right) \log{\left(e^{1} \right)}} = 0$$
Solve this equationThe roots of this equation
$$x_{1} = - \frac{\sqrt{3}}{3}$$
$$x_{2} = \frac{\sqrt{3}}{3}$$
You also need to calculate the limits of y '' for arguments seeking to indeterminate points of a function:
Points where there is an indetermination:
$$x_{1} = 0$$
$$\lim_{x \to 0^-}\left(- \frac{2 \cdot \left(3 + \frac{2}{x^{2} \cdot \left(1 - \frac{1}{x^{2}}\right)}\right)}{x^{4} \cdot \left(1 - \frac{1}{x^{2}}\right) \log{\left(e^{1} \right)}}\right) = \infty$$
Let's take the limit$$\lim_{x \to 0^+}\left(- \frac{2 \cdot \left(3 + \frac{2}{x^{2} \cdot \left(1 - \frac{1}{x^{2}}\right)}\right)}{x^{4} \cdot \left(1 - \frac{1}{x^{2}}\right) \log{\left(e^{1} \right)}}\right) = \infty$$
Let's take the limit- limits are equal, then skip the corresponding 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:
Concave at the intervals
$$\left[- \frac{\sqrt{3}}{3}, \frac{\sqrt{3}}{3}\right]$$
Convex at the intervals
$$\left(-\infty, - \frac{\sqrt{3}}{3}\right] \cup \left[\frac{\sqrt{3}}{3}, \infty\right)$$