Math Problem Statement

Use the change of base formula to compute log_8 (1/3). Round your answer to the nearest thousandth.

Solution

To solve the problem log813\log_8 \frac{1}{3} using the change of base formula, follow these steps:

The change of base formula is:

logba=logalogb\log_b a = \frac{\log a}{\log b}

Here:

  • b=8b = 8
  • a=13a = \frac{1}{3}

Step 1: Apply the formula

log813=log13log8\log_8 \frac{1}{3} = \frac{\log \frac{1}{3}}{\log 8}

Step 2: Compute log13\log \frac{1}{3}

Using the property of logarithms: log13=log1log3=0log3=log3\log \frac{1}{3} = \log 1 - \log 3 = 0 - \log 3 = -\log 3

Thus: log813=log3log8\log_8 \frac{1}{3} = \frac{-\log 3}{\log 8}

Step 3: Compute log3\log 3 and log8\log 8

Using a calculator:

  • log30.4771\log 3 \approx 0.4771
  • log80.9031\log 8 \approx 0.9031

Substitute these values: log813=0.47710.90310.5285\log_8 \frac{1}{3} = \frac{-0.4771}{0.9031} \approx -0.5285

Step 4: Round to the nearest thousandth

log8130.529\log_8 \frac{1}{3} \approx -0.529

Final Answer:

0.529\boxed{-0.529}

Let me know if you need further clarification or steps!


Expanding the topic:

  1. How does the change of base formula work conceptually?
  2. What is the property of logarithms used in simplifying log13\log \frac{1}{3}?
  3. Can you apply this to log20.25\log_2 0.25?
  4. Why are logarithmic functions important in real-world applications?
  5. How do the properties of logarithms simplify calculations without a calculator?

Tip:

Always double-check your logarithmic values with a calculator or software for precision.

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Math Problem Analysis

Mathematical Concepts

Logarithms
Change of Base Formula
Logarithmic Properties

Formulas

log_b a = log(a) / log(b)

Theorems

Logarithmic Change of Base Theorem

Suitable Grade Level

Grades 10-12