Given the inequality:
$$\cot{\left(\frac{x}{3} - \frac{\pi}{6} \right)} > 0$$
To solve this inequality, we must first solve the corresponding equation:
$$\cot{\left(\frac{x}{3} - \frac{\pi}{6} \right)} = 0$$
Solve:
$$x_{1} = - \pi$$
$$x_{1} = - \pi$$
This roots
$$x_{1} = - \pi$$
is the points with change the sign of the inequality expression.
First define with the sign to the leftmost point:
$$x_{0} < x_{1}$$
For example, let's take the point
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \pi - \frac{1}{10}$$
=
$$- \pi - \frac{1}{10}$$
substitute to the expression
$$\cot{\left(\frac{x}{3} - \frac{\pi}{6} \right)} > 0$$
$$\cot{\left(\frac{- \pi - \frac{1}{10}}{3} - \frac{\pi}{6} \right)} > 0$$
tan(1/30) > 0
the solution of our inequality is:
$$x < - \pi$$
_____
\
-------ο-------
x1