Math Problem Statement

Write the expression as a sum and/or difference of logarithms. Express powers as factors: ln(2x√(1 + 4x) / (x - 8)^4), x > 8.

Solution

To solve the expression ln(2x1+4x(x8)4)\ln \left( \frac{2x \sqrt{1 + 4x}}{(x - 8)^4} \right), we need to simplify it by applying logarithmic properties. These properties include:

  1. ln(ab)=lnalnb\ln \left( \frac{a}{b} \right) = \ln a - \ln b (logarithm of a quotient)
  2. ln(ab)=lna+lnb\ln (a \cdot b) = \ln a + \ln b (logarithm of a product)
  3. ln(an)=nlna\ln (a^n) = n \ln a (logarithm of a power)

Step-by-step solution:

  1. Apply the quotient rule:
    ln(2x1+4x(x8)4)=ln(2x1+4x)ln((x8)4)\ln \left( \frac{2x \sqrt{1 + 4x}}{(x - 8)^4} \right) = \ln (2x \sqrt{1 + 4x}) - \ln ((x - 8)^4)

  2. Apply the power rule to the second term:
    Since ln((x8)4)=4ln(x8)\ln ((x - 8)^4) = 4 \ln (x - 8), we get: ln(2x1+4x)4ln(x8)\ln (2x \sqrt{1 + 4x}) - 4 \ln (x - 8)

  3. Simplify the first term using the product rule: ln(2x1+4x)=ln(2x)+ln(1+4x)\ln (2x \sqrt{1 + 4x}) = \ln (2x) + \ln (\sqrt{1 + 4x})

  4. Apply the power rule to the square root term: Since ln(1+4x)=12ln(1+4x)\ln (\sqrt{1 + 4x}) = \frac{1}{2} \ln (1 + 4x), the expression becomes: ln(2x)+12ln(1+4x)4ln(x8)\ln (2x) + \frac{1}{2} \ln (1 + 4x) - 4 \ln (x - 8)

  5. Simplify further using the product rule for ln(2x)\ln(2x): ln(2x)=ln2+lnx\ln(2x) = \ln 2 + \ln x

Final simplified expression:

ln2+lnx+12ln(1+4x)4ln(x8)\ln 2 + \ln x + \frac{1}{2} \ln (1 + 4x) - 4 \ln (x - 8)

This is the simplified expression as a sum and difference of logarithms, with powers expressed as factors.

Would you like any further details or explanations? Here are some related questions to deepen your understanding:

  1. How do you apply the quotient rule for logarithms in other cases?
  2. What happens if the base of the logarithm is not ee (natural log)?
  3. Can you explain why ln(a)=12ln(a)\ln (\sqrt{a}) = \frac{1}{2} \ln(a)?
  4. How would the expression change if the exponent on (x8)(x - 8) were negative?
  5. How can you further simplify the expression if xx has specific values?

Tip: Always check if powers or square roots can be simplified early in logarithmic expressions.

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Math Problem Analysis

Mathematical Concepts

Logarithmic Expressions
Quotient Rule
Power Rule
Product Rule

Formulas

ln(a / b) = ln(a) - ln(b)
ln(a^n) = n ln(a)
ln(ab) = ln(a) + ln(b)

Theorems

Logarithmic Properties

Suitable Grade Level

Grades 10-12