Can you help me to find the solution of logarithm equation

In summary, the inequality can be rewritten as ##\frac12 \log_2(2x - 1) < \frac12 \log_2(x)##. From here, it can be solved in 3 steps.
  • #1
Helly123
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Homework Statement


$$\log_2 \sqrt{2x-1} < \log_4 x$$

Homework Equations

The Attempt at a Solution


$$\log_2 \sqrt{2x-1} < \log_4 x$$
$$\log_2 {2x-1}^{1/2} < \log_2 \sqrt{x}$$
$$1/2 \log_2 {(2x-1)} - \log_2 \sqrt{x} < 0$$
$$ 1/2 \log_2 {\frac{(2x-1)}{ x}} < 0$$
$$ -1/2 \log_2 {(2x-1) x} < 0$$
$$ 1/2 \log_2 {(2x^2-x)} > 0$$
$$ \log_2 {\sqrt{(2x^2-x)}} >\log_2 {1} $$
$$2x^2 - x > 1$$
$$2x^2 - x - 1 = 0$$
$$(2x + 1)(x -1) = 0$$
$$x < -1/2 \ \ or \ \ x > 1$$

but I get wrong answers. How to find the right answer? can you help me?
 
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  • #2
Helly123 said:

Homework Statement


$$\log_2 \sqrt{2x-1} < \log_4 x$$

Homework Equations

The Attempt at a Solution


$$\log_2 {2x-1}^{1/2} < \log_2 \sqrt{x}$$
You miss parentheses on the left side and the base of logatrithm is 4 instead of 2 on the right side.
 
  • #3
ehild said:
You miss parentheses on the left side and the base of logatrithm is 4 instead of 2 on the right side.
That's exactly what the question is..
 
  • #4
Helly123 said:
That's exactly what the question is..
No. The question is :
##
\log_2 \sqrt{2x-1} < \log_4 x##
 
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  • #5
I can't really follow all your steps because it's almost 2am over here and it's been a long day. However, your second line can be written as

##\frac12 \log_2(2x - 1) < \frac12 \log_2(x)##

from here it should be solved in 3 steps
 
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  • #6
ehild said:
No. The question is :
##
\log_2 \sqrt{2x-1} < \log_4 x##
ive changed it
 
  • #7
Marc Rindermann said:
I can't really follow all your steps because it's almost 2am over here and it's been a long day. However, your second line can be written as

##\frac12 \log_2(2x - 1) < \frac12 \log_2(x)##

from here it should be solved in 3 steps
I see.. that's true. Thank you
 

1. What is a logarithm equation?

A logarithm equation is an equation in the form of logb(x) = y, where b is the base, x is the argument, and y is the result. It is used to solve for the value of x when given a specific base and result.

2. How do I solve a logarithm equation?

To solve a logarithm equation, you can use the properties of logarithms, such as the product rule, quotient rule, and power rule. You can also rewrite the equation in exponential form and solve for x using basic algebraic techniques.

3. What are the common bases used in logarithm equations?

The most commonly used bases in logarithm equations are base 10 and base e (also known as the natural log). However, any positive real number can be used as a base in logarithm equations.

4. Can you provide an example of solving a logarithm equation?

Sure! Let's say we have the equation log2(x) = 4. To solve for x, we can rewrite the equation in exponential form as 24 = x. Therefore, x = 16.

5. Are there any restrictions when solving logarithm equations?

Yes, there are a few restrictions to keep in mind when solving logarithm equations. The argument (x) must be positive, and the base (b) cannot be 1. Additionally, the result (y) cannot be negative for a real solution to exist.

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