Mister Exam

cotx>=1 inequation

A inequation with variable

The solution

You have entered [src]
cot(x) >= 1
$$\cot{\left(x \right)} \geq 1$$
cot(x) >= 1
Detail solution
Given the inequality:
$$\cot{\left(x \right)} \geq 1$$
To solve this inequality, we must first solve the corresponding equation:
$$\cot{\left(x \right)} = 1$$
Solve:
Given the equation
$$\cot{\left(x \right)} = 1$$
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:
$$x_{0} \leq x_{1}$$
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
$$\cot{\left(x \right)} \geq 1$$
$$\cot{\left(- \frac{1}{10} + \frac{\pi}{4} \right)} \geq 1$$
   /1    pi\     
tan|-- + --| >= 1
   \10   4 /     

the solution of our inequality is:
$$x \leq \frac{\pi}{4}$$
 _____          
      \    
-------•-------
       x1
Rapid solution 2 [src]
    pi 
(0, --]
    4  
$$x\ in\ \left(0, \frac{\pi}{4}\right]$$
x in Interval.Lopen(0, pi/4)
Rapid solution [src]
   /     pi       \
And|x <= --, 0 < x|
   \     4        /
$$x \leq \frac{\pi}{4} \wedge 0 < x$$
(0 < x)∧(x <= pi/4)