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Help me with this math problem

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MIMIC

Banned
Here's the problem:

Write the given expression as a single logarithm: 3ln(e^2 - e) - 3

Here's how I arrived at my answer:

3lne^2 - 3lne^3 - 3
lne^6 - lne^3 - 3
ln(e^6 / e^3) - 3
ln(e^2) - 3
2lne - 3 <----My answer

Here's the correct answer: 3ln(e - 1)

What the freak am I doing wrong (or forgetting)?
 

Dilbert

Member
MIMIC said:
Here's the problem:

Write the given expression as a single logarithm: 3ln(e^2 - e) - 3
I believe your first step is wrong. ln(e² - e) is not the same thing as (ln e²) - (ln e).

Here's how I'd solve the problem. First, factor out e from the first term:

3 ln (e)(e - 1) - 3

Next, use this law of logarithms: log AB = log A + log B

3 ln e + 3 ln (e - 1) - 3

Of course, this can be simplified since ln e = 1:

3 + 3 ln (e - 1) - 3

The two 3 terms cancel out, leaving 3 ln (e - 1), which is what you want.
 
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