Can you help me to find the solution of logarithm equation

AI Thread Summary
The discussion centers on solving the logarithmic inequality $$\log_2 \sqrt{2x-1} < \log_4 x$$. Participants point out that the logarithm on the right should be converted to base 2 for consistency. The solution involves manipulating the logarithmic expressions and simplifying them to find the critical points. The correct approach leads to the inequality $$2x^2 - x > 1$$, which factors to find the solutions. Overall, clarity in the logarithmic bases and proper algebraic manipulation are essential for arriving at the correct answer.
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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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.
 
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..
 
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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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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ehild said:
No. The question is :
##
\log_2 \sqrt{2x-1} < \log_4 x##
ive changed it
 
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
 
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