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Ch. 3 - Derivatives
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 18e

Suppose the position of an object moving horizontally along a line after t seconds is given by the following functions s = f(t), where s is measured in feet, with s > 0 corresponding to positions right of the origin.
On what intervals is the speed increasing?
f(t) = 18t - 3t2; 0 ≤ t ≤ 8

검증된 단계별 안내
1
Step 1: Understand that speed is the absolute value of velocity. To find when speed is increasing, we need to analyze the velocity function and its derivative.
Step 2: Find the velocity function v(t) by differentiating the position function f(t) with respect to time t. This gives v(t) = f'(t) = 18 - 6t.
Step 3: Determine when the velocity is increasing by finding the derivative of the velocity function, which is the acceleration a(t). So, a(t) = v'(t) = -6.
Step 4: Since the acceleration a(t) = -6 is constant and negative, the velocity is always decreasing. However, speed increases when velocity and acceleration have opposite signs.
Step 5: Analyze the intervals where velocity is negative (v(t) < 0) because speed increases when velocity is negative and decreasing. Solve 18 - 6t < 0 to find the interval where speed is increasing.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
6m
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주요 개념

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

Position Function

The position function, denoted as s = f(t), describes the location of an object at any given time t. In this case, f(t) = 18t - 3t² represents a quadratic function where the position is influenced by both linear and quadratic terms. Understanding this function is crucial for analyzing the object's motion and determining its speed and acceleration.
추천 영상:
가이드 코스
5:20
Relations and Functions

Velocity and Speed

Velocity is the rate of change of position with respect to time, calculated as the derivative of the position function, v(t) = f'(t). Speed, being the absolute value of velocity, indicates how fast the object is moving regardless of direction. To determine when speed is increasing, one must analyze the behavior of the velocity function over the specified interval.
추천 영상:
가이드 코스
06:29
Derivatives Applied To Velocity

Acceleration

Acceleration is the rate of change of velocity with respect to time, represented as the derivative of the velocity function, a(t) = v'(t). When acceleration is positive, the speed of the object is increasing. Thus, to find the intervals where speed is increasing, one must identify where the acceleration function is greater than zero within the given time frame.
추천 영상:
가이드 코스
06:15
Derivatives Applied To Acceleration