Mister Exam

ctg(x)<=1 inequation

A inequation with variable

The solution

You have entered [src]
cot(x) <= 1
cot(x)1\cot{\left(x \right)} \leq 1
cot(x) <= 1
Detail solution
Given the inequality:
cot(x)1\cot{\left(x \right)} \leq 1
To solve this inequality, we must first solve the corresponding equation:
cot(x)=1\cot{\left(x \right)} = 1
Solve:
Given the equation
cot(x)=1\cot{\left(x \right)} = 1
transform
cot(x)1=0\cot{\left(x \right)} - 1 = 0
cot(x)1=0\cot{\left(x \right)} - 1 = 0
Do replacement
w=cot(x)w = \cot{\left(x \right)}
Move free summands (without w)
from left part to right part, we given:
w=1w = 1
We get the answer: w = 1
do backward replacement
cot(x)=w\cot{\left(x \right)} = w
substitute w:
x1=π4x_{1} = \frac{\pi}{4}
x1=π4x_{1} = \frac{\pi}{4}
This roots
x1=π4x_{1} = \frac{\pi}{4}
is the points with change the sign of the inequality expression.
First define with the sign to the leftmost point:
x0x1x_{0} \leq x_{1}
For example, let's take the point
x0=x1110x_{0} = x_{1} - \frac{1}{10}
=
110+π4- \frac{1}{10} + \frac{\pi}{4}
=
110+π4- \frac{1}{10} + \frac{\pi}{4}
substitute to the expression
cot(x)1\cot{\left(x \right)} \leq 1
cot(110+π4)1\cot{\left(- \frac{1}{10} + \frac{\pi}{4} \right)} \leq 1
   /1    pi\     
tan|-- + --| <= 1
   \10   4 /     

but
   /1    pi\     
tan|-- + --| >= 1
   \10   4 /     

Then
xπ4x \leq \frac{\pi}{4}
no execute
the solution of our inequality is:
xπ4x \geq \frac{\pi}{4}
         _____  
        /
-------•-------
       x1
Rapid solution [src]
   /pi             \
And|-- <= x, x < pi|
   \4              /
π4xx<π\frac{\pi}{4} \leq x \wedge x < \pi
(x < pi)∧(pi/4 <= x)
Rapid solution 2 [src]
 pi     
[--, pi)
 4      
x in [π4,π)x\ in\ \left[\frac{\pi}{4}, \pi\right)
x in Interval.Ropen(pi/4, pi)