Skip to main content
Ch. 3 - Derivatives
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
All textbooksBriggs 3rd EditionCh. 3 - DerivativesProblem 3.6.60c
Chapter 3, Problem 3.6.60c

{Use of Tech} Spring runoff The flow of a small stream is monitored for 90 days between May 1 and August 1. The total water that flows past a gauging station is given by v(t) = <matrix 2x2> where V is measured in cubic feet and t is measured in days, with t=0 corresponding to May 1.
c. Describe the flow of the stream over the 3-month period. Specifically, when is the flow rate a maximum?

Verified step by step guidance
1
To describe the flow of the stream over the 3-month period, we need to analyze the function v(t) that represents the total volume of water that flows past the gauging station. The flow rate of the stream is given by the derivative of v(t), denoted as v'(t).
Calculate the derivative v'(t) to find the flow rate function. This involves differentiating the given function v(t) with respect to time t.
Once you have v'(t), identify the critical points by setting v'(t) = 0 and solving for t. These critical points are potential candidates for maximum or minimum flow rates.
To determine whether each critical point is a maximum or minimum, use the second derivative test. Calculate the second derivative v''(t) and evaluate it at each critical point. If v''(t) is negative at a critical point, the flow rate is at a maximum there.
Finally, evaluate the flow rate at the endpoints of the interval (t = 0 and t = 90) and compare these values with the flow rates at the critical points to determine when the flow rate is at its maximum over the entire 90-day period.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
9m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Flow Rate

Flow rate refers to the volume of fluid that passes through a given surface per unit of time. In this context, it is essential to understand how the flow rate of the stream varies over the specified period. The flow rate can be represented mathematically as the derivative of the volume function, indicating how quickly water is flowing at any given time.
Recommended video:
04:16
Intro To Related Rates

Integration

Integration is a fundamental concept in calculus that allows us to calculate the total accumulation of quantities, such as the total volume of water flowing over time. In this scenario, integrating the flow rate function over the 90-day period will provide the total volume of water that has flowed past the gauging station, which is crucial for understanding the stream's behavior.
Recommended video:
05:04
Introduction to Indefinite Integrals

Critical Points

Critical points are values of the independent variable where the derivative of a function is zero or undefined, indicating potential maximum or minimum values. To determine when the flow rate is at its maximum, one must find the critical points of the flow rate function and evaluate them to identify the maximum flow rate during the monitoring period.
Recommended video:
04:50
Critical Points
Related Practice
Textbook Question

Another way to approximate derivatives is to use the centered difference quotient: f' (a) ≈ f(a+h) - f(a- h) / 2h. Again, consider f(x) = √x.

c. Explain why it is not necessary to use negative values of h in the table of part (b).

Textbook Question

Derivatives from a graph If possible, evaluate the following derivatives using the graphs of f and f'. <IMAGE>

c. (f^-1)'(f(2))

1
views
Textbook Question

A rectangular swimming pool 10 ft wide by 20 ft long and of uniform depth is being filled with water.

c. At what rate is the water level rising if the pool is filled at a rate of 10ft³/min?

Textbook Question

62–65. {Use of Tech} Graphing f and f'

c. Verify that the zeros of f' correspond to points at which f has a horizontal tangent line.

f(x) = (x−1) sin^−1 x on [−1,1]

Textbook Question

Suppose a stone is thrown vertically upward from the edge of a cliff on Earth with an initial velocity of 19.6 m/s from a height of 24.5 m above the ground. The height (in meters) of the stone above the ground t seconds after it is thrown is s(t) = -4.9t²+19.6t+24.5.

c. What is the height of the stone at the highest point?

Textbook Question

Witch of Agnesi Let y(x²+4)=8 (see figure). <IMAGE>

c. Solve the equation y(x²+4)=8 for y to find an explicit expression for y and then calculate dy/dx.