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Ch. 4 - Inverse, Exponential, and Logarithmic Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
5장, 문제 97

Given that log10 2 ≈ 0.3010 and log10 3 ≈ 0.4771, find each logarithm without using a calculator. log10 9/4

검증된 단계별 안내
1
Recognize that the logarithm of a quotient can be expressed as the difference of logarithms: \(\log_{10} \left( \frac{9}{4} \right) = \log_{10} 9 - \log_{10} 4\).
Express 9 and 4 in terms of their prime factors: \(9 = 3^2\) and \(4 = 2^2\).
Use the logarithm power rule to rewrite the logs: \(\log_{10} 9 = \log_{10} (3^2) = 2 \log_{10} 3\) and \(\log_{10} 4 = \log_{10} (2^2) = 2 \log_{10} 2\).
Substitute the given approximate values into the expression: \(2 \log_{10} 3 - 2 \log_{10} 2\) becomes \(2 \times 0.4771 - 2 \times 0.3010\).
Simplify the expression by performing the multiplications and then subtracting to find the value of \(\log_{10} \left( \frac{9}{4} \right)\).

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주요 개념

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Properties of Logarithms

Logarithms have specific properties that simplify calculations, such as the product rule (log_b(xy) = log_b x + log_b y), quotient rule (log_b(x/y) = log_b x - log_b y), and power rule (log_b(x^n) = n log_b x). These allow breaking down complex expressions into simpler parts.
추천 영상:
5:36
Change of Base Property

Change of Base and Given Logarithm Values

Using known logarithm values, like log_10 2 ≈ 0.3010 and log_10 3 ≈ 0.4771, helps compute other logarithms by expressing numbers in terms of these bases. This avoids calculator use by rewriting numbers as products or quotients of known values.
추천 영상:
5:36
Change of Base Property

Expressing Numbers as Products or Quotients of Prime Factors

To use given logarithm values effectively, numbers should be factored into primes or known bases. For example, 9/4 can be written as (3^2)/(2^2), enabling the use of logarithm properties and known values to find the logarithm of the entire expression.
추천 영상:
가이드 코스
6:29
Factor Using Special Product Formulas