ctg-1<0 inequation

Given the inequality:
$$\cot{\left(x \right)} - 1 < 0$$
To solve this inequality, we must first solve the corresponding equation:
$$\cot{\left(x \right)} - 1 = 0$$
Solve:
Given the equation
$$\cot{\left(x \right)} - 1 = 0$$
transform
$$\cot{\left(x \right)} - 1 = 0$$
$$\cot{\left(x \right)} - 1 = 0$$
Do replacement
$$w = \cot{\left(x \right)}$$
Move free summands (without w)
from left part to right part, we given:
$$w = 1$$
We get the answer: w = 1
do backward replacement
$$\cot{\left(x \right)} = w$$
substitute w:
$$x_{1} = \frac{\pi}{4}$$
$$x_{1} = \frac{\pi}{4}$$
This roots
$$x_{1} = \frac{\pi}{4}$$
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
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \frac{1}{10} + \frac{\pi}{4}$$
=
$$- \frac{1}{10} + \frac{\pi}{4}$$
substitute to the expression
$$\cot{\left(x \right)} - 1 < 0$$
$$-1 + \cot{\left(- \frac{1}{10} + \frac{\pi}{4} \right)} < 0$$

        /1    pi\    
-1 + tan|-- + --| < 0
        \10   4 /    

but

        /1    pi\    
-1 + tan|-- + --| > 0
        \10   4 /    

Then
$$x < \frac{\pi}{4}$$
no execute
the solution of our inequality is:
$$x > \frac{\pi}{4}$$

         _____  
        /
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       x1