Compute the exact value of log 8 + log(1/8) using logarithm identities.
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A0
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B1
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C2
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Dlog(64)
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ENone of these
Answer
Correct Answer: 0
Explanation
Introduction / Context:This is a direct application of the product rule of logarithms and the defining property log(1) = 0.
Given Data / Assumptions:
- Expression: log 8 + log(1/8)
- Common base for both logs (base 10 is standard).
Concept / Approach:Use log A + log B = log(A·B). Multiplying 8 by its reciprocal gives 1, whose logarithm is zero in any base.
Step-by-Step Solution:
log 8 + log(1/8) = log(8 × 1/8) = log(1) = 0Verification / Alternative check:Since log(1) is 0 for any allowed base, the result is base-independent as long as the base is consistent across terms.
Why Other Options Are Wrong:1 or 2 would require the product inside the log to be 10 or 100 (base 10), which it is not. log(64) represents a different expression entirely.
Common Pitfalls:Occasionally students attempt to add arguments (8 + 1/8) rather than multiply; always add logs by multiplying their arguments.
Final Answer:0