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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 99

Work each problem. Which of the following is equivalent to 2 ln(3x) for x > 0?
A. ln 9 + ln x
B. ln 6x
C. ln 6 + ln x
D. ln 9x2

검증된 단계별 안내
1
Recall the logarithmic property that states: \(a \ln b = \ln b^a\). This means you can rewrite \(2 \ln(3x)\) as \(\ln((3x)^2)\).
Apply the exponent inside the logarithm: \((3x)^2 = 3^2 \times x^2 = 9x^2\). So, \(2 \ln(3x) = \ln(9x^2)\).
Recognize that \(\ln(9x^2)\) can be separated using the logarithm product rule: \(\ln(ab) = \ln a + \ln b\). Therefore, \(\ln(9x^2) = \ln 9 + \ln x^2\).
Use the power rule for logarithms on \(\ln x^2\): \(\ln x^2 = 2 \ln x\). So, \(\ln(9x^2) = \ln 9 + 2 \ln x\).
Compare the expression \(\ln(9x^2)\) with the given options to identify which one matches \(2 \ln(3x)\).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m
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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Properties of Logarithms

Logarithms have specific properties that simplify expressions, such as the product rule (ln a + ln b = ln(ab)) and the power rule (k ln a = ln(a^k)). These rules allow rewriting complex logarithmic expressions into simpler or equivalent forms.
추천 영상:
5:36
Change of Base Property

Power Rule for Logarithms

The power rule states that multiplying a logarithm by a constant is equivalent to taking the logarithm of the argument raised to that constant: k ln(a) = ln(a^k). This is essential for rewriting expressions like 2 ln(3x) as ln((3x)^2).
추천 영상:
5:50
Power Rules

Domain Restrictions in Logarithmic Functions

Logarithmic functions are defined only for positive arguments. For ln(3x), the domain restriction x > 0 ensures the argument 3x is positive, which is necessary for the expression to be valid and for applying logarithmic properties correctly.
추천 영상:
3:51
Domain Restrictions of Composed Functions