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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 1
Chapter 3, Problem 1

Explain the difference between the average rate of change and the instantaneous rate of change of a function f.

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The average rate of change of a function f over an interval [a, b] is calculated as the change in the function's value over the change in the interval. It is given by the formula: \( \frac{f(b) - f(a)}{b - a} \). This represents the slope of the secant line connecting the points (a, f(a)) and (b, f(b)) on the graph of the function.
The instantaneous rate of change of a function f at a point x = c is the derivative of the function at that point, denoted as f'(c). It represents the slope of the tangent line to the graph of the function at the point (c, f(c)).
Conceptually, the average rate of change gives us an overall rate of change between two points, while the instantaneous rate of change provides the rate at a specific point, capturing the function's behavior at that exact location.
To find the instantaneous rate of change, we take the limit of the average rate of change as the interval [a, b] shrinks to the point c, which is mathematically expressed as: \( \lim_{h \to 0} \frac{f(c+h) - f(c)}{h} \).
In summary, the average rate of change is a measure over an interval, while the instantaneous rate of change is a measure at a single point, and is found using the derivative of the function.

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Key Concepts

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

Average Rate of Change

The average rate of change of a function f over an interval [a, b] is defined as the change in the function's value divided by the change in the input value. Mathematically, it is expressed as (f(b) - f(a)) / (b - a). This concept provides a measure of how much the function's output changes on average for a given change in input over the specified interval.
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Instantaneous Rate of Change

The instantaneous rate of change of a function f at a specific point x is the limit of the average rate of change as the interval shrinks to zero. It is represented mathematically as the derivative f'(x), which gives the slope of the tangent line to the function at that point. This concept is crucial for understanding how a function behaves at a precise moment.
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Derivative

The derivative of a function is a fundamental concept in calculus that represents the instantaneous rate of change of the function with respect to its variable. It is defined as the limit of the difference quotient as the interval approaches zero. Derivatives are essential for analyzing the behavior of functions, including finding maxima, minima, and points of inflection.
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Related Practice
Textbook Question

Use the precise definition of a limit to prove the following limits. Specify a relationship between ε and δ that guarantees the limit exists.

lim x→a (mx+b)=ma+b, for any constants a, b, and m

Textbook Question

Two boats leave a port at the same time, one traveling west at 20 mi/hr and the other traveling southwest ( 45° south of west) at 15 mi/hr. After 30 minutes, how far apart are the boats and at what rate is the distance between them changing? (Hint: Use the Law of Cosines.)

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Textbook Question

9–61. Evaluate and simplify y'.

y = (v / v+1)^4/3