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ctg(3x)>1/3 inequation

A inequation with variable

The solution

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cot(3*x) > 1/3
$$\cot{\left(3 x \right)} > \frac{1}{3}$$
cot(3*x) > 1/3
Detail solution
Given the inequality:
$$\cot{\left(3 x \right)} > \frac{1}{3}$$
To solve this inequality, we must first solve the corresponding equation:
$$\cot{\left(3 x \right)} = \frac{1}{3}$$
Solve:
Given the equation
$$\cot{\left(3 x \right)} = \frac{1}{3}$$
transform
$$\cot{\left(3 x \right)} - \frac{1}{3} = 0$$
$$\cot{\left(3 x \right)} - \frac{1}{3} = 0$$
Do replacement
$$w = \cot{\left(3 x \right)}$$
Move free summands (without w)
from left part to right part, we given:
$$w = \frac{1}{3}$$
We get the answer: w = 1/3
do backward replacement
$$\cot{\left(3 x \right)} = w$$
substitute w:
$$x_{1} = \frac{\operatorname{acot}{\left(\frac{1}{3} \right)}}{3}$$
$$x_{1} = \frac{\operatorname{acot}{\left(\frac{1}{3} \right)}}{3}$$
This roots
$$x_{1} = \frac{\operatorname{acot}{\left(\frac{1}{3} \right)}}{3}$$
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
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \frac{1}{10} + \frac{\operatorname{acot}{\left(\frac{1}{3} \right)}}{3}$$
=
$$- \frac{1}{10} + \frac{\operatorname{acot}{\left(\frac{1}{3} \right)}}{3}$$
substitute to the expression
$$\cot{\left(3 x \right)} > \frac{1}{3}$$
$$\cot{\left(3 \left(- \frac{1}{10} + \frac{\operatorname{acot}{\left(\frac{1}{3} \right)}}{3}\right) \right)} > \frac{1}{3}$$
-cot(3/10 - acot(1/3)) > 1/3

the solution of our inequality is:
$$x < \frac{\operatorname{acot}{\left(\frac{1}{3} \right)}}{3}$$
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Rapid solution [src]
   /              /      /   /  atan(3/4)   pi\\                                                             \\
   |              |      |sin|- --------- + --||      /    _________________________________________________\||
   |              |      |   \      6       6 /|      |   /    2/  atan(3/4)   pi\      2/  atan(3/4)   pi\ |||
And|0 < x, x < -I*|I*atan|---------------------| + log|  /  cos |- --------- + --| + sin |- --------- + --| |||
   |              |      |   /  atan(3/4)   pi\|      \\/       \      6       6 /       \      6       6 / /||
   |              |      |cos|- --------- + --||                                                             ||
   \              \      \   \      6       6 //                                                             //
$$0 < x \wedge x < - i \left(\log{\left(\sqrt{\sin^{2}{\left(- \frac{\operatorname{atan}{\left(\frac{3}{4} \right)}}{6} + \frac{\pi}{6} \right)} + \cos^{2}{\left(- \frac{\operatorname{atan}{\left(\frac{3}{4} \right)}}{6} + \frac{\pi}{6} \right)}} \right)} + i \operatorname{atan}{\left(\frac{\sin{\left(- \frac{\operatorname{atan}{\left(\frac{3}{4} \right)}}{6} + \frac{\pi}{6} \right)}}{\cos{\left(- \frac{\operatorname{atan}{\left(\frac{3}{4} \right)}}{6} + \frac{\pi}{6} \right)}} \right)}\right)$$
(0 < x)∧(x < -i*(i*atan(sin(-atan(3/4)/6 + pi/6)/cos(-atan(3/4)/6 + pi/6)) + log(sqrt(cos(-atan(3/4)/6 + pi/6)^2 + sin(-atan(3/4)/6 + pi/6)^2))))