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Ch. 3 - Derivatives
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 3.8.19a

Area The area A of a triangle with sides of lengths a and b enclosing an angle of measure θ is
A = (1/2) ab sinθ.


a. How is dA/dt related to dθ/dt if a and b are constant?

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1
Start by understanding the formula for the area of a triangle: A = (1/2)ab sin(θ). Here, a and b are constants, and θ is the variable that changes over time.
To find how dA/dt is related to dθ/dt, apply the chain rule of differentiation. Since a and b are constants, differentiate A with respect to θ: dA/dθ = (1/2)ab cos(θ).
Now, use the chain rule to relate dA/dt to dθ/dt. The chain rule states that dA/dt = (dA/dθ) * (dθ/dt).
Substitute the expression for dA/dθ from step 2 into the chain rule formula: dA/dt = (1/2)ab cos(θ) * dθ/dt.
This equation shows that the rate of change of the area with respect to time, dA/dt, is directly proportional to the rate of change of the angle with respect to time, dθ/dt, and depends on the cosine of the angle θ.

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

The derivative represents the rate of change of a function with respect to a variable. In this context, dA/dt is the derivative of the area A with respect to time t, indicating how the area changes as the angle θ changes over time.
추천 영상:

Chain Rule

The chain rule is a fundamental theorem in calculus used to differentiate composite functions. It allows us to find the derivative of a function with respect to an intermediate variable, such as θ, when the function is expressed in terms of another variable, like t. Here, it helps relate dA/dt to dθ/dt.
추천 영상:
05:02
Intro to the Chain Rule

Trigonometric Functions

Trigonometric functions, such as sine, are essential in relating angles to side lengths in triangles. The function sinθ is used in the formula for the area of a triangle, and understanding its derivative is crucial for determining how changes in θ affect the area A when differentiating A = (1/2) ab sinθ.
추천 영상:
가이드 코스
6:04
Introduction to Trigonometric Functions