Solving Logarithmic Equations: Find log[base 2]log[base 3]a = 2

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Discussion Overview

The discussion revolves around solving the logarithmic equation log[base 2](log[base 3]a) = 2, focusing on the methods and definitions related to logarithms. The scope includes mathematical reasoning and problem-solving techniques.

Discussion Character

  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant asks how to find the value of 'a' in the equation log[base 2](log[base 3]a) = 2.
  • Another participant prompts for the definition of a logarithm and what the original poster has tried so far.
  • It is suggested to consider the inverse of logarithms and how they can be calculated easily.
  • A participant outlines the steps to solve the equation, stating that if log[base a] x = y, then a^y = x, leading to log[base 3] a = 4.
  • Using the identity log[base x] y = (ln y)/(ln x), the participant derives ln a = 4 ln 3 and concludes that a = e^(4 ln 3), resulting in a = 81.
  • Another participant reiterates the same steps but suggests that the identity may not be necessary for the solution.
  • A later reply acknowledges a mistake in understanding the problem.

Areas of Agreement / Disagreement

There is no consensus on the necessity of using the identity involving natural logarithms, as one participant suggests it may not be needed while another includes it in their solution process. The discussion remains unresolved regarding the optimal approach to solving the equation.

Contextual Notes

Some participants express uncertainty about the representation of logarithmic bases and the steps involved in solving the equation, indicating potential limitations in their understanding of logarithmic identities.

AzureNight
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I have a question I need to do which I'm stuck on:

find a

log[base 2](log[base 3]a) = 2

How would I do that? And sorry about the crude representation of the base, but I'm not sure how to do a small 2 or 3 on the computer.

Edit: oh damn, wrong forum. I guess it has to be moved to the appropriate one for homework questions.
 
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What have you tried so far? What is the definition of a logarithm?
 
suggest you think about the inverse of logs of an integer base and how easily they can be worked out
 
Ok well. log[base a] x = y then a^y= x, by definition.

Then in this case, 2^2 = log[base 3] a
log[base3]a = 4

Indentity- log[base x] y = (ln y)/(ln x) Hopefully uve learned this.

ln a = 4 ln 3

make both sides the exponents of e.
a= e^(4 ln3 )

Therefore, a = 81.
 
Gib Z said:
Ok well. log[base a] x = y then a^y= x, by definition.

Then in this case, 2^2 = log[base 3] a
log[base3]a = 4

Indentity- log[base x] y = (ln y)/(ln x) Hopefully uve learned this.

ln a = 4 ln 3

make both sides the exponents of e.
a= e^(4 ln3 )

Therefore, a = 81.
no need for e or your identity, just use your 1st line defn again
 
o yea that should have been obvious, my bad
 

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