Use the properties of logaritms to expand the expression

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The discussion focuses on expanding the logarithmic expression ln((4x^5 - x - 1)(√(x - 7)) / (x^2 + 1)^3) using properties of logarithms. It emphasizes the correct notation, clarifying that "ln" represents the natural logarithm, not "in." The correct approach involves rewriting the expression as ln(A) + ln(B) - ln(C), applying the logarithmic properties for multiplication and division. The participant's initial attempt contains several errors, including misuse of multiplication symbols and misunderstanding of logarithmic functions. Overall, the conversation aims to guide the correct application of logarithmic properties in the given expression.
pooker
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Homework Statement



IN * ((4x^5 - x -1)(square root x-7)) / (x^2 + 1)^3





The Attempt at a Solution



in(4x^5 - x - 1) + in(square root x-7) - in(x^2 + 1)^3

in(4x^5 - x - 1) + 1/2in(x-7) - 3in(x^2 +1)

5in4x - inx - 1 + 1/2(inx -in7) - 3 (2inx + in)


I know that's not right but its all I can think of at the moment.
 
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pooker said:

Homework Statement



IN * ((4x^5 - x -1)(square root x-7)) / (x^2 + 1)^3





The Attempt at a Solution



in(4x^5 - x - 1) + in(square root x-7) - in(x^2 + 1)^3

in(4x^5 - x - 1) + 1/2in(x-7) - 3in(x^2 +1)

5in4x - inx - 1 + 1/2(inx -in7) - 3 (2inx + in)


I know that's not right but its all I can think of at the moment.

First off, it's not in, it's ln (ell en), short for logarithm naturalis or something close to that. Before being able to help you out, can you confirm that this is the problem?
ln \frac{(4x^5 - x - 1)(\sqrt{x - 7})}{(x^2 + 1)^3}

If so, then an expression of the form ln[(AB)/C] can be rewritten as ln A + ln B - ln C.
Then because the individual expressions B and C have exponents, you can use the property of logarithms that ln a^b = b ln a.

Mistakes in your work:
1. You start with IN *. I've already mentioned that it is LN, but the mistake here is the mulitiplication symbol. ln is a function, not a number, so it's meaningless to think of using it to multiply.
2. In your later work you have "3in(x^2 +1)" and in the next line you have "3 (2inx + in)". This suggests to me that you think that "in" is a number. It's not. 2 inx + in is meaningless.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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