37. Plutonium-239 The half-life of the plutonium isotope is 24,360 years. If 10 g of plutonium is released into the atmosphere by a nuclear accident, how many years will it take for 80% of the isotope to decay?
Ch. 7 - Transcendental Functions
7장, 문제 7.3.23
In Exercises 7–26, find the derivative of y with respect to x, t, or θ, as appropriate.
y = e^(cost+lnt)
검증된 단계별 안내1
Identify the variable with respect to which you need to differentiate. Since the function is given as \(y = e^{\cos t + \ln t}\), and the expression involves \(t\), we will differentiate with respect to \(t\).
Recall the chain rule for differentiation: if \(y = e^{u(t)}\), then \(\frac{dy}{dt} = e^{u(t)} \cdot \frac{du}{dt}\), where \(u(t) = \cos t + \ln t\) in this case.
Find the derivative of the exponent function \(u(t) = \cos t + \ln t\). Differentiate each term separately: \(\frac{d}{dt}(\cos t) = -\sin t\) and \(\frac{d}{dt}(\ln t) = \frac{1}{t}\).
Combine the derivatives of the terms to get \(\frac{du}{dt} = -\sin t + \frac{1}{t}\).
Write the final expression for the derivative using the chain rule: \(\frac{dy}{dt} = e^{\cos t + \ln t} \cdot \left(-\sin t + \frac{1}{t}\right)\).

비슷한 문제에 대한 검증된 영상 답변:
이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
4m주요 개념
질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.
Chain Rule
The chain rule is used to differentiate composite functions. It states that the derivative of a function composed of another function is the derivative of the outer function evaluated at the inner function times the derivative of the inner function. This is essential when differentiating expressions like e^(cos t + ln t).
추천 영상:
Intro to the Chain Rule
Derivatives of Exponential Functions
The derivative of an exponential function e^u, where u is a function of the variable, is e^u multiplied by the derivative of u. Recognizing this helps in differentiating y = e^(cos t + ln t) by first identifying the exponent as a function and then applying the chain rule.
추천 영상:
Derivatives of General Exponential Functions
Derivatives of Trigonometric and Logarithmic Functions
Knowing the derivatives of cos t and ln t is crucial. The derivative of cos t with respect to t is -sin t, and the derivative of ln t is 1/t. These derivatives are used when applying the chain rule to find the derivative of the exponent in the given function.
추천 영상:
Derivative of the Natural Logarithmic Function
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Indeterminate Powers and Products
Find the limits in Exercises 53–68.
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In Exercises 115–126, use logarithmic differentiation or the method in Example 6 to find the derivative of y with respect to the given independent variable.
124. x^(sin y) = ln y
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교과서 질문
132. What is special about the functions
f(x) = arcsin((1/√(x²+1)) and g(x)=arctan(1/x)?
Explain.
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교과서 질문
Use l’Hôpital’s rule to find the limits in Exercises 7–52.
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교과서 질문
135. Find the area of the “triangular” region in the first quadrant that is bounded above by the curve y = e^(2x), below by the curve y = e^x, and on the right by the line x = ln(3).
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