Is $\frac{\ln{|x|}}{x}=\ln{|x^{-x}|}$? Explained by y $\ln{x}=\ln{x^y}$ Rule

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Discussion Overview

The discussion centers on the equation \(\frac{\ln{|x|}}{x}=\ln{|x^{-x}|}\) and whether it can be justified using the rule \(y \ln{x}=\ln{x^y}\). Participants explore the implications of this rule in relation to logarithmic properties and absolute values.

Discussion Character

  • Debate/contested

Main Points Raised

  • Some participants assert that the equation holds true based on the rule \(y \ln{x}=\ln{x^y}\).
  • Others agree with the application of the rule but express uncertainty about bringing the exponent inside the absolute value in all cases.
  • A participant points out that their answer key typically allows for such simplifications, indicating a potential inconsistency in the application of the rules.
  • Another participant challenges the generalization of bringing the power inside the absolute signs, suggesting that it may not be valid in all scenarios.

Areas of Agreement / Disagreement

Participants do not reach a consensus; there are competing views regarding the validity of the equation and the application of logarithmic rules.

Contextual Notes

There are limitations regarding the assumptions made about the properties of logarithms and absolute values, particularly in the context of the generalization of the rules discussed.

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Is [math]\frac{\ln{|x|}}{x}=\ln{|x^{-x}|}[/math] because of the rule [math] y \ln{x}=\ln{x^y}[/math]?
 
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Yep! And in general, you can bring the exponent inside the absolute value.
 
Rido12 said:
Yep! And in general, you can bring the exponent inside the absolute value.

Oh cool, usually my answer key makes these sorts of simplifications but it didn't for this one.
 
find_the_fun said:
Is [math]\frac{\ln{|x|}}{x}=\ln{|x^{-x}|}[/math] because of the rule [math] y \ln{x}=\ln{x^y}[/math]?

Applying that rule gives us:
$$\frac{\ln{|x|}}{x}=\ln{\left(|x|^{1/x}\right)}$$
And I'm afraid we can't generally bring that power inside the absolute signs.
 

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