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$$\frac{\sqrt{- \frac{x + 1}{x - 1}} \left(1 - \frac{x + 1}{x - 1}\right) \left(\frac{1 - \frac{x + 1}{x - 1}}{x + 1} - \frac{2}{x + 1} - \frac{2}{x - 1}\right)}{4 \left(x + 1\right)} = 0$$
Solve this equationThe roots of this equation
$$x_{1} = - \frac{1}{2}$$
You also need to calculate the limits of y '' for arguments seeking to indeterminate points of a function:
Points where there is an indetermination:
$$x_{1} = 1$$
$$\lim_{x \to 1^-}\left(\frac{\sqrt{- \frac{x + 1}{x - 1}} \left(1 - \frac{x + 1}{x - 1}\right) \left(\frac{1 - \frac{x + 1}{x - 1}}{x + 1} - \frac{2}{x + 1} - \frac{2}{x - 1}\right)}{4 \left(x + 1\right)}\right) = \infty$$
$$\lim_{x \to 1^+}\left(\frac{\sqrt{- \frac{x + 1}{x - 1}} \left(1 - \frac{x + 1}{x - 1}\right) \left(\frac{1 - \frac{x + 1}{x - 1}}{x + 1} - \frac{2}{x + 1} - \frac{2}{x - 1}\right)}{4 \left(x + 1\right)}\right) = \infty i$$
- the limits are not equal, so
$$x_{1} = 1$$
- 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:
Concave at the intervals
$$\left[- \frac{1}{2}, \infty\right)$$
Convex at the intervals
$$\left(-\infty, - \frac{1}{2}\right]$$