Given the inequality:
$$\cot{\left(3 x + \frac{\pi}{3} \right)} < \sqrt{3}$$
To solve this inequality, we must first solve the corresponding equation:
$$\cot{\left(3 x + \frac{\pi}{3} \right)} = \sqrt{3}$$
Solve:
$$x_{1} = - \frac{\pi}{18}$$
$$x_{1} = - \frac{\pi}{18}$$
This roots
$$x_{1} = - \frac{\pi}{18}$$
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
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \frac{\pi}{18} - \frac{1}{10}$$
=
$$- \frac{\pi}{18} - \frac{1}{10}$$
substitute to the expression
$$\cot{\left(3 x + \frac{\pi}{3} \right)} < \sqrt{3}$$
$$\cot{\left(3 \left(- \frac{\pi}{18} - \frac{1}{10}\right) + \frac{\pi}{3} \right)} < \sqrt{3}$$
/3 pi\ ___
tan|-- + --| < \/ 3
\10 3 /
but
/3 pi\ ___
tan|-- + --| > \/ 3
\10 3 /
Then
$$x < - \frac{\pi}{18}$$
no execute
the solution of our inequality is:
$$x > - \frac{\pi}{18}$$
_____
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