Which is Greater: $\log_9 25$ or $\log_4 9$?

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Discussion Overview

The discussion centers around comparing the values of $\log_9 25$ and $\log_4 9$. Participants explore the mathematical properties and calculations related to logarithms to determine which of the two expressions is greater. The scope includes mathematical reasoning and comparisons of logarithmic values.

Discussion Character

  • Mathematical reasoning

Main Points Raised

  • Some participants propose methods for calculating or estimating the values of $\log_9 25$ and $\log_4 9$.
  • Others discuss properties of logarithms that may influence the comparison, such as change of base formulas.
  • A later reply questions the assumptions made in the calculations and suggests verifying the results through different approaches.

Areas of Agreement / Disagreement

Participants have not reached a consensus on which logarithmic expression is greater, and multiple approaches and calculations are being considered.

anemone
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Which of the following two is greater?

$\log_9 25$ and $\log_4 9$
 
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anemone said:
Which of the following two is greater?

$\log_9 25$ and $\log_4 9$

$9^{1.5} = 3^3 = 27$
$4^{1.5} = 2^3 = 8$

so $\log_9 27$ = $\log_4 8$
or $\log_9 25$ < $\log_9 27$ = $\log_4 8$ < $\log_4 9$

hence $\log_4 9$ is greater
 
Very good, kaliprasad and thanks for participating!

My solution:

$\log_9 25<\log_9 26<\dfrac{\log_4 26}{\log_4 9}<\dfrac{\log_4 26}{\log_4 8}=\dfrac{\log_4 (26)^2}{3}=\dfrac{\log_4 676}{3}<\dfrac{\log_4 729}{3}=\log_4 9$
 
anemone said:
Very good, kaliprasad and thanks for participating!

My solution:

$\log_9 25<\log_9 26<\dfrac{\log_4 26}{\log_4 9}<\dfrac{\log_4 26}{\log_4 8}=\dfrac{\log_4 (26)^2}{3}=\dfrac{\log_4 676}{3}<\dfrac{\log_4 729}{3}=\log_4 9$

it should be $\log_9 26=\dfrac{\log_4 26}{\log_4 9}$ (a typo)
 

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