Natural logs solve ln⁡((x-1)/(x-3))=2

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Discussion Overview

The discussion revolves around solving the equation ln((x-1)/(x-3))=2, focusing on the manipulation of natural logarithms and algebraic rearrangements to isolate x. Participants seek clarification on the steps involved in arriving at the correct solution.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant presents their solution as x = 2/(e²-1) and calculates it to approximately 0.3130352855.
  • Another participant indicates that their lecturer provided a different solution, x = (3e²-1)/(e²-1), which approximates to 3.313035285, and seeks guidance on how to derive this result.
  • A later reply outlines a method to manipulate the original equation, suggesting that multiplying both sides by (x-3) leads to x(e² - 1) = 3e² - 1, which can be rearranged to isolate x.
  • One participant requests further assistance in transposing the formula to solve for x, indicating difficulty in understanding the algebraic steps.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there are differing solutions presented and ongoing requests for clarification on the algebraic process.

Contextual Notes

Some participants express uncertainty regarding the steps to isolate x, and there are unresolved questions about the correctness of the different solutions provided.

blackfriars
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hi , hope someone can help as i can't get past a certain step
the natural logs is the problem
ln⁡((x-1)/(x-3))=2
i can get to this point here -1 = e_x^2-x-3
-1+3=x(ⅇ^2-1)
2 = x(ⅇ^2-1)
2/((ⅇ^2-1) )=x((ⅇ^2-1)/(ⅇ^2-1))
X = 2/(ⅇ^2-1)
the solution i got was this x= (2/(ⅇ^2-1)) → 0.3130352855

but the lecturer gave a solution of
(3ⅇ^2-1)/(ⅇ^2-1) = 3.313035285 how do i get to this
 
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blackfriars said:
hi , hope someone can help as i can't get past a certain step
the natural logs is the problem
ln⁡((x-1)/(x-3))=2
i can get to this point here -1 = e_x^2-x-3
-1+3=x(ⅇ^2-1)
2 = x(ⅇ^2-1)
2/((ⅇ^2-1) )=x((ⅇ^2-1)/(ⅇ^2-1))
X = 2/(ⅇ^2-1)
the solution i got was this x= (2/(ⅇ^2-1)) → 0.3130352855

but the lecturer gave a solution of
(3ⅇ^2-1)/(ⅇ^2-1) = 3.313035285 how do i get to this
If $\ln\left(\frac{x-1}{x-3}\right) = 2$ then $\frac{x-1}{x-3} = e^2.$ Multiply both sides by $x-3$ to get $x-1 = (x-3)e^2.$ Then rearrange that as $x(e^2 - 1) = 3e^2 - 1$. That gives $x = \dfrac{3e^2-1}{e^2-1} \approx 3.313035...$.
 
hi sorry for the questions but i cannot transpose the formula to make x the subject could you show the workings for making x the subject
thanks
 
Same topic and a working found http://mathhelpboards.com/pre-algebra-algebra-2/logs-22167-new.html. Thread closed - please continue discussion in linked thread.

blackfriars, please do not post duplicate topics; thanks. :D
 

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