Skip to main content
Ch. 7 - Transcendental Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
7장, 문제 7.3.19

In Exercises 7–26, find the derivative of y with respect to x, t, or θ, as appropriate.
y = ln(3te^(-t))

검증된 단계별 안내
1
Identify the function given: \(y = \ln(3te^{-t})\). Notice that the argument of the logarithm is a product of two functions: \$3t$ and $e^{-t}$.
Use the logarithm property to simplify the expression before differentiating: \(\ln(3te^{-t}) = \ln(3t) + \ln(e^{-t})\).
Further simplify using the logarithm of an exponential: \(\ln(e^{-t}) = -t\), so the function becomes \(y = \ln(3t) - t\).
Differentiate each term separately with respect to \(t\). For \(\ln(3t)\), use the chain rule: \(\frac{d}{dt}[\ln(3t)] = \frac{1}{3t} \times 3 = \frac{1}{t}\). For \(-t\), the derivative is \(-1\).
Combine the derivatives to write the final derivative: \(\frac{dy}{dt} = \frac{1}{t} - 1\).

비슷한 문제에 대한 검증된 영상 답변:

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

주요 개념

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

Derivative of the Natural Logarithm Function

The derivative of ln(u), where u is a differentiable function of a variable, is (1/u) times the derivative of u. This rule allows us to differentiate logarithmic expressions by first identifying the inner function and then applying the chain rule.
추천 영상:
05:18
Derivative of the Natural Logarithmic Function

Product Rule for Differentiation

When differentiating a product of two functions, the product rule states that the derivative is the first function times the derivative of the second plus the second function times the derivative of the first. This is essential when the argument of the logarithm is a product, like 3t and e^(-t).
추천 영상:
05:18
The Product Rule

Derivative of the Exponential Function

The derivative of e^f(t), where f(t) is a function of t, is e^f(t) times the derivative of f(t). Recognizing this helps differentiate terms like e^(-t), which appear inside the logarithm's argument.
추천 영상:
04:50
Derivatives of General Exponential Functions