Mister Exam

Other calculators

log(1/2)*log(sqrt(5))*(x-4)>-1 inequation

A inequation with variable

The solution

You have entered [src]
            /  ___\             
log(1/2)*log\\/ 5 /*(x - 4) > -1
$$\log{\left(\frac{1}{2} \right)} \log{\left(\sqrt{5} \right)} \left(x - 4\right) > -1$$
(log(1/2)*log(sqrt(5)))*(x - 4) > -1
Detail solution
Given the inequality:
$$\log{\left(\frac{1}{2} \right)} \log{\left(\sqrt{5} \right)} \left(x - 4\right) > -1$$
To solve this inequality, we must first solve the corresponding equation:
$$\log{\left(\frac{1}{2} \right)} \log{\left(\sqrt{5} \right)} \left(x - 4\right) = -1$$
Solve:
Given the equation:
log(1/2)*log(sqrt(5))*(x-4) = -1

Expand expressions:
2*log(2)*log(5) - x*log(2)*log(5)/2 = -1

Reducing, you get:
1 + 2*log(2)*log(5) - x*log(2)*log(5)/2 = 0

Expand brackets in the left part
1 + 2*log2log5 - x*log2log5/2 = 0

Move free summands (without x)
from left part to right part, we given:
$$- \frac{x \log{\left(2 \right)} \log{\left(5 \right)}}{2} + 2 \log{\left(2 \right)} \log{\left(5 \right)} = -1$$
Divide both parts of the equation by (2*log(2)*log(5) - x*log(2)*log(5)/2)/x
x = -1 / ((2*log(2)*log(5) - x*log(2)*log(5)/2)/x)

We get the answer: x = 4 + 2/(log(2)*log(5))
$$x_{1} = \frac{2}{\log{\left(2 \right)} \log{\left(5 \right)}} + 4$$
$$x_{1} = \frac{2}{\log{\left(2 \right)} \log{\left(5 \right)}} + 4$$
This roots
$$x_{1} = \frac{2}{\log{\left(2 \right)} \log{\left(5 \right)}} + 4$$
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
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \frac{1}{10} + \left(\frac{2}{\log{\left(2 \right)} \log{\left(5 \right)}} + 4\right)$$
=
$$\frac{2}{\log{\left(2 \right)} \log{\left(5 \right)}} + \frac{39}{10}$$
substitute to the expression
$$\log{\left(\frac{1}{2} \right)} \log{\left(\sqrt{5} \right)} \left(x - 4\right) > -1$$
$$\log{\left(\frac{1}{2} \right)} \log{\left(\sqrt{5} \right)} \left(-4 + \left(\frac{2}{\log{\left(2 \right)} \log{\left(5 \right)}} + \frac{39}{10}\right)\right) > -1$$
 /  1          2      \           /  ___\     
-|- -- + -------------|*log(2)*log\\/ 5 / > -1
 \  10   log(2)*log(5)/                       

the solution of our inequality is:
$$x < \frac{2}{\log{\left(2 \right)} \log{\left(5 \right)}} + 4$$
 _____          
      \    
-------ο-------
       x1
Solving inequality on a graph
Rapid solution [src]
   /             2*(1 + 2*log(2)*log(5))\
And|-oo < x, x < -----------------------|
   \                  log(2)*log(5)     /
$$-\infty < x \wedge x < \frac{2 \left(1 + 2 \log{\left(2 \right)} \log{\left(5 \right)}\right)}{\log{\left(2 \right)} \log{\left(5 \right)}}$$
(-oo < x)∧(x < 2*(1 + 2*log(2)*log(5))/(log(2)*log(5)))
Rapid solution 2 [src]
      2*(1 + 2*log(2)*log(5)) 
(-oo, -----------------------)
           log(2)*log(5)      
$$x\ in\ \left(-\infty, \frac{2 \left(1 + 2 \log{\left(2 \right)} \log{\left(5 \right)}\right)}{\log{\left(2 \right)} \log{\left(5 \right)}}\right)$$
x in Interval.open(-oo, 2*(1 + 2*log(2)*log(5))/(log(2)*log(5)))