Partial Fraction Question: Simplifying ln(2) and ln(3) to ln(8/3) in 8/5 form

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Discussion Overview

The discussion revolves around simplifying a logarithmic expression derived from a partial fraction problem. Participants explore how to express the result, initially given as a combination of logarithms, in a specific simplified form using logarithmic properties.

Discussion Character

  • Mathematical reasoning

Main Points Raised

  • One participant presents the expression \( \frac{24}{5} \ln(2) - \frac{8}{5} \ln(3) \) and notes that the system requires it to be simplified to \( \frac{8}{5} \ln(8/3) \).
  • Another participant asserts that the two forms are equivalent and references the logarithmic property that allows for the transformation of coefficients into exponents.
  • A third participant explains that if the expression were \( \frac{24}{5} \ln{2} - \frac{8}{5} \ln{3} \), it could be rewritten using logarithmic identities to achieve the desired form of \( \frac{8}{5} \ln{8/3} \).
  • A later reply confirms the transformation by showing the steps leading to \( \frac{8}{5} \ln(8/3) \) and emphasizes the use of logarithmic properties to arrive at the conclusion.

Areas of Agreement / Disagreement

Participants generally agree on the mathematical properties involved in simplifying the logarithmic expression, but there is no explicit consensus on the initial form or the steps taken to achieve the final result.

Contextual Notes

The discussion assumes familiarity with logarithmic identities and properties, but does not clarify all steps leading to the final expression, leaving some assumptions implicit.

stripedcat
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Without being too concerned how we got there. The answer to a partial fraction question a friend and I are doing is

24/5 ln(2) - 8/5ln(3)

The system does not accept this answer however, it wants the simplified form

8/5 ln (8/3)

We're not sure how to get that form.

More specifically

8/5 (ln(8)-ln(3))

It's the ln(8) we're not sure about.
 
Last edited:
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If you and your friend's answer was:

$$\frac{24}{5}\ln(2)-\frac{8}{5}\ln(3)$$

then it would be equivalent to the answer expected by "the system."

Recall the logarithmic property:

$$b\cdot\log_{a}(c)=\log_{a}\left(c^b\right)$$
 
If you had $(24/5)\ln{2} - (8/5)\ln{3}$ instead of $(26/5)\ln{2} - (8/5)\ln{3}$ you would get the desired $(8/5)\ln{8/3}$. To see this, use the formula $b \ln{a} = \ln{a^b}$ to write

$(24/5)\ln{2} = (8/5)(3\ln{2}) = (8/5) \ln{2^3} = (8/5)\ln{8}$.

Then $(24/5)\ln{2} - (8/5)\ln{3} = (8/5)(\ln{8} - \ln{3})$, which, as you mentioned, equals $(8/5)\ln{8/3}$.
 
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Sooo

24/5 ln(2) - 8/5 ln(3)

(24/5)/(8/5)=3

8/5 (3ln(2) - ln(3))

2^3 = 8

ln(8)-ln(3)

8/5 ln(8/3)

Ace.
 
Last edited:

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