Chapter 2.7, Problem 13E

BuyFind*arrow_forward*

8th Edition

James Stewart

ISBN: 9781285740621

Textbook Problem

(a) Find the average rate of change of the area of a circle

with respect to its radius *r* as *r* changes from

(i) 2 to 3

(ii) 2 to 2.5

(iii) 2 to 2.1

(b) Find the instantaneous rate of change when *r* = 2.

(c) Show that the rate of change of the area of a circle with respect to its radius (at any *r)* is equal to the circumference of the circle. Try to explain geometrically why this is true by drawing a circle whose radius is increased by an amount

To determine

**Part (a):**

**To find: **The average rate of change of the area of a circle when r changes from

(i) 2 to 3

(ii) 2 to 2.5

(iii) 2 to 2.1

Explanation

**1) Concept:**

Use concept of average rate of change

**2) Formula:**

I. Area of circle:

II. The average rate of change of the area of a circle with respect to radius r over [

**3) Given:**

(i) 2 to 3

(ii) 2 to 2.5

Â (iii) 2 to 2.1

**4) Calculation:**

**(i)Â **By using average rate of change formula,

Substitute

Thus,

**(ii)Â **By using average rate of change formula,

Substitute

Sect-2.1 P-1ESect-2.1 P-2ESect-2.1 P-3ESect-2.1 P-4ESect-2.1 P-5ESect-2.1 P-6ESect-2.1 P-7ESect-2.1 P-8ESect-2.1 P-9ESect-2.1 P-10E

Sect-2.1 P-11ESect-2.1 P-12ESect-2.1 P-13ESect-2.1 P-14ESect-2.1 P-15ESect-2.1 P-16ESect-2.1 P-17ESect-2.1 P-18ESect-2.1 P-19ESect-2.1 P-20ESect-2.1 P-21ESect-2.1 P-22ESect-2.1 P-23ESect-2.1 P-24ESect-2.1 P-25ESect-2.1 P-26ESect-2.1 P-27ESect-2.1 P-28ESect-2.1 P-29ESect-2.1 P-30ESect-2.1 P-31ESect-2.1 P-32ESect-2.1 P-33ESect-2.1 P-34ESect-2.1 P-35ESect-2.1 P-36ESect-2.1 P-37ESect-2.1 P-38ESect-2.1 P-39ESect-2.1 P-40ESect-2.1 P-41ESect-2.1 P-42ESect-2.1 P-43ESect-2.1 P-44ESect-2.1 P-45ESect-2.1 P-46ESect-2.1 P-47ESect-2.1 P-48ESect-2.1 P-49ESect-2.1 P-50ESect-2.1 P-51ESect-2.1 P-52ESect-2.1 P-53ESect-2.1 P-54ESect-2.1 P-55ESect-2.1 P-56ESect-2.1 P-57ESect-2.1 P-58ESect-2.1 P-59ESect-2.1 P-60ESect-2.1 P-61ESect-2.2 P-1ESect-2.2 P-2ESect-2.2 P-3ESect-2.2 P-4ESect-2.2 P-5ESect-2.2 P-6ESect-2.2 P-7ESect-2.2 P-8ESect-2.2 P-9ESect-2.2 P-10ESect-2.2 P-11ESect-2.2 P-12ESect-2.2 P-13ESect-2.2 P-14ESect-2.2 P-15ESect-2.2 P-16ESect-2.2 P-17ESect-2.2 P-18ESect-2.2 P-19ESect-2.2 P-20ESect-2.2 P-21ESect-2.2 P-22ESect-2.2 P-23ESect-2.2 P-24ESect-2.2 P-25ESect-2.2 P-26ESect-2.2 P-27ESect-2.2 P-28ESect-2.2 P-29ESect-2.2 P-30ESect-2.2 P-31ESect-2.2 P-32ESect-2.2 P-33ESect-2.2 P-34ESect-2.2 P-35ESect-2.2 P-36ESect-2.2 P-37ESect-2.2 P-38ESect-2.2 P-39ESect-2.2 P-40ESect-2.2 P-41ESect-2.2 P-42ESect-2.2 P-43ESect-2.2 P-44ESect-2.2 P-45ESect-2.2 P-46ESect-2.2 P-47ESect-2.2 P-48ESect-2.2 P-49ESect-2.2 P-50ESect-2.2 P-51ESect-2.2 P-52ESect-2.2 P-53ESect-2.2 P-54ESect-2.2 P-55ESect-2.2 P-56ESect-2.2 P-57ESect-2.2 P-58ESect-2.2 P-59ESect-2.2 P-60ESect-2.2 P-61ESect-2.2 P-62ESect-2.2 P-63ESect-2.2 P-64ESect-2.2 P-65ESect-2.3 P-1ESect-2.3 P-2ESect-2.3 P-3ESect-2.3 P-4ESect-2.3 P-5ESect-2.3 P-6ESect-2.3 P-7ESect-2.3 P-8ESect-2.3 P-9ESect-2.3 P-10ESect-2.3 P-11ESect-2.3 P-12ESect-2.3 P-13ESect-2.3 P-14ESect-2.3 P-15ESect-2.3 P-16ESect-2.3 P-17ESect-2.3 P-18ESect-2.3 P-19ESect-2.3 P-20ESect-2.3 P-21ESect-2.3 P-22ESect-2.3 P-23ESect-2.3 P-24ESect-2.3 P-25ESect-2.3 P-26ESect-2.3 P-27ESect-2.3 P-28ESect-2.3 P-29ESect-2.3 P-30ESect-2.3 P-31ESect-2.3 P-32ESect-2.3 P-33ESect-2.3 P-34ESect-2.3 P-35ESect-2.3 P-36ESect-2.3 P-37ESect-2.3 P-38ESect-2.3 P-39ESect-2.3 P-40ESect-2.3 P-41ESect-2.3 P-42ESect-2.3 P-43ESect-2.3 P-44ESect-2.3 P-45ESect-2.3 P-46ESect-2.3 P-47ESect-2.3 P-48ESect-2.3 P-49ESect-2.3 P-50ESect-2.3 P-51ESect-2.3 P-52ESect-2.3 P-53ESect-2.3 P-54ESect-2.3 P-55ESect-2.3 P-56ESect-2.3 P-57ESect-2.3 P-58ESect-2.3 P-59ESect-2.3 P-60ESect-2.3 P-61ESect-2.3 P-62ESect-2.3 P-63ESect-2.3 P-64ESect-2.3 P-65ESect-2.3 P-66ESect-2.3 P-67ESect-2.3 P-68ESect-2.3 P-69ESect-2.3 P-70ESect-2.3 P-71ESect-2.3 P-72ESect-2.3 P-73ESect-2.3 P-74ESect-2.3 P-75ESect-2.3 P-76ESect-2.3 P-77ESect-2.3 P-78ESect-2.3 P-79ESect-2.3 P-80ESect-2.3 P-81ESect-2.3 P-82ESect-2.3 P-83ESect-2.3 P-84ESect-2.3 P-85ESect-2.3 P-86ESect-2.3 P-87ESect-2.3 P-88ESect-2.3 P-89ESect-2.3 P-90ESect-2.3 P-91ESect-2.3 P-92ESect-2.3 P-93ESect-2.3 P-94ESect-2.3 P-95ESect-2.3 P-96ESect-2.3 P-97ESect-2.3 P-98ESect-2.3 P-99ESect-2.3 P-100ESect-2.3 P-101ESect-2.3 P-102ESect-2.3 P-103ESect-2.3 P-104ESect-2.3 P-105ESect-2.3 P-106ESect-2.3 P-107ESect-2.3 P-108ESect-2.3 P-109ESect-2.3 P-110ESect-2.4 P-1ESect-2.4 P-2ESect-2.4 P-3ESect-2.4 P-4ESect-2.4 P-5ESect-2.4 P-6ESect-2.4 P-7ESect-2.4 P-8ESect-2.4 P-9ESect-2.4 P-10ESect-2.4 P-11ESect-2.4 P-12ESect-2.4 P-13ESect-2.4 P-14ESect-2.4 P-15ESect-2.4 P-16ESect-2.4 P-17ESect-2.4 P-18ESect-2.4 P-19ESect-2.4 P-20ESect-2.4 P-21ESect-2.4 P-22ESect-2.4 P-23ESect-2.4 P-24ESect-2.4 P-25ESect-2.4 P-26ESect-2.4 P-27ESect-2.4 P-28ESect-2.4 P-29ESect-2.4 P-30ESect-2.4 P-31ESect-2.4 P-32ESect-2.4 P-33ESect-2.4 P-34ESect-2.4 P-35ESect-2.4 P-36ESect-2.4 P-37ESect-2.4 P-38ESect-2.4 P-39ESect-2.4 P-40ESect-2.4 P-41ESect-2.4 P-42ESect-2.4 P-43ESect-2.4 P-44ESect-2.4 P-45ESect-2.4 P-46ESect-2.4 P-47ESect-2.4 P-48ESect-2.4 P-49ESect-2.4 P-50ESect-2.4 P-51ESect-2.4 P-52ESect-2.4 P-53ESect-2.4 P-54ESect-2.4 P-55ESect-2.4 P-56ESect-2.4 P-57ESect-2.4 P-58ESect-2.5 P-1ESect-2.5 P-2ESect-2.5 P-3ESect-2.5 P-4ESect-2.5 P-5ESect-2.5 P-6ESect-2.5 P-7ESect-2.5 P-8ESect-2.5 P-9ESect-2.5 P-10ESect-2.5 P-11ESect-2.5 P-12ESect-2.5 P-13ESect-2.5 P-14ESect-2.5 P-15ESect-2.5 P-16ESect-2.5 P-17ESect-2.5 P-18ESect-2.5 P-19ESect-2.5 P-20ESect-2.5 P-21ESect-2.5 P-22ESect-2.5 P-23ESect-2.5 P-24ESect-2.5 P-25ESect-2.5 P-26ESect-2.5 P-27ESect-2.5 P-28ESect-2.5 P-29ESect-2.5 P-30ESect-2.5 P-31ESect-2.5 P-32ESect-2.5 P-33ESect-2.5 P-34ESect-2.5 P-35ESect-2.5 P-36ESect-2.5 P-37ESect-2.5 P-38ESect-2.5 P-39ESect-2.5 P-40ESect-2.5 P-41ESect-2.5 P-42ESect-2.5 P-43ESect-2.5 P-44ESect-2.5 P-45ESect-2.5 P-46ESect-2.5 P-47ESect-2.5 P-48ESect-2.5 P-49ESect-2.5 P-50ESect-2.5 P-51ESect-2.5 P-52ESect-2.5 P-53ESect-2.5 P-54ESect-2.5 P-55ESect-2.5 P-56ESect-2.5 P-57ESect-2.5 P-58ESect-2.5 P-59ESect-2.5 P-60ESect-2.5 P-61ESect-2.5 P-62ESect-2.5 P-63ESect-2.5 P-64ESect-2.5 P-65ESect-2.5 P-66ESect-2.5 P-67ESect-2.5 P-68ESect-2.5 P-69ESect-2.5 P-70ESect-2.5 P-71ESect-2.5 P-72ESect-2.5 P-73ESect-2.5 P-74ESect-2.5 P-75ESect-2.5 P-76ESect-2.5 P-77ESect-2.5 P-78ESect-2.5 P-79ESect-2.5 P-80ESect-2.5 P-81ESect-2.5 P-82ESect-2.5 P-83ESect-2.5 P-84ESect-2.5 P-85ESect-2.5 P-86ESect-2.5 P-87ESect-2.5 P-88ESect-2.5 P-89ESect-2.5 P-90ESect-2.6 P-1ESect-2.6 P-2ESect-2.6 P-3ESect-2.6 P-4ESect-2.6 P-5ESect-2.6 P-6ESect-2.6 P-7ESect-2.6 P-8ESect-2.6 P-9ESect-2.6 P-10ESect-2.6 P-11ESect-2.6 P-12ESect-2.6 P-13ESect-2.6 P-14ESect-2.6 P-15ESect-2.6 P-16ESect-2.6 P-17ESect-2.6 P-18ESect-2.6 P-19ESect-2.6 P-20ESect-2.6 P-21ESect-2.6 P-22ESect-2.6 P-23ESect-2.6 P-24ESect-2.6 P-25ESect-2.6 P-26ESect-2.6 P-27ESect-2.6 P-28ESect-2.6 P-29ESect-2.6 P-30ESect-2.6 P-31ESect-2.6 P-32ESect-2.6 P-33ESect-2.6 P-34ESect-2.6 P-35ESect-2.6 P-36ESect-2.6 P-37ESect-2.6 P-38ESect-2.6 P-39ESect-2.6 P-40ESect-2.6 P-41ESect-2.6 P-42ESect-2.6 P-43ESect-2.6 P-44ESect-2.6 P-45ESect-2.6 P-46ESect-2.6 P-47ESect-2.6 P-48ESect-2.6 P-49ESect-2.6 P-50ESect-2.6 P-51ESect-2.6 P-52ESect-2.6 P-53ESect-2.6 P-54ESect-2.6 P-55ESect-2.6 P-56ESect-2.6 P-57ESect-2.6 P-58ESect-2.6 P-59ESect-2.6 P-60ESect-2.6 P-61ESect-2.6 P-62ESect-2.7 P-1ESect-2.7 P-2ESect-2.7 P-3ESect-2.7 P-4ESect-2.7 P-5ESect-2.7 P-6ESect-2.7 P-7ESect-2.7 P-8ESect-2.7 P-9ESect-2.7 P-10ESect-2.7 P-11ESect-2.7 P-12ESect-2.7 P-13ESect-2.7 P-14ESect-2.7 P-15ESect-2.7 P-16ESect-2.7 P-17ESect-2.7 P-18ESect-2.7 P-19ESect-2.7 P-20ESect-2.7 P-21ESect-2.7 P-22ESect-2.7 P-23ESect-2.7 P-24ESect-2.7 P-25ESect-2.7 P-26ESect-2.7 P-27ESect-2.7 P-28ESect-2.7 P-29ESect-2.7 P-30ESect-2.7 P-31ESect-2.7 P-32ESect-2.7 P-33ESect-2.7 P-34ESect-2.7 P-35ESect-2.7 P-36ESect-2.8 P-1ESect-2.8 P-2ESect-2.8 P-3ESect-2.8 P-4ESect-2.8 P-5ESect-2.8 P-6ESect-2.8 P-7ESect-2.8 P-8ESect-2.8 P-9ESect-2.8 P-10ESect-2.8 P-11ESect-2.8 P-12ESect-2.8 P-13ESect-2.8 P-14ESect-2.8 P-15ESect-2.8 P-16ESect-2.8 P-17ESect-2.8 P-18ESect-2.8 P-19ESect-2.8 P-20ESect-2.8 P-21ESect-2.8 P-22ESect-2.8 P-23ESect-2.8 P-24ESect-2.8 P-25ESect-2.8 P-26ESect-2.8 P-27ESect-2.8 P-28ESect-2.8 P-29ESect-2.8 P-30ESect-2.8 P-31ESect-2.8 P-32ESect-2.8 P-33ESect-2.8 P-34ESect-2.8 P-35ESect-2.8 P-36ESect-2.8 P-37ESect-2.8 P-38ESect-2.8 P-39ESect-2.8 P-40ESect-2.8 P-41ESect-2.8 P-42ESect-2.8 P-43ESect-2.8 P-44ESect-2.8 P-45ESect-2.8 P-46ESect-2.8 P-47ESect-2.8 P-48ESect-2.8 P-49ESect-2.8 P-50ESect-2.9 P-1ESect-2.9 P-2ESect-2.9 P-3ESect-2.9 P-4ESect-2.9 P-5ESect-2.9 P-6ESect-2.9 P-7ESect-2.9 P-8ESect-2.9 P-9ESect-2.9 P-10ESect-2.9 P-11ESect-2.9 P-12ESect-2.9 P-13ESect-2.9 P-14ESect-2.9 P-15ESect-2.9 P-16ESect-2.9 P-17ESect-2.9 P-18ESect-2.9 P-19ESect-2.9 P-20ESect-2.9 P-21ESect-2.9 P-22ESect-2.9 P-23ESect-2.9 P-24ESect-2.9 P-25ESect-2.9 P-26ESect-2.9 P-27ESect-2.9 P-28ESect-2.9 P-29ESect-2.9 P-30ESect-2.9 P-31ESect-2.9 P-32ESect-2.9 P-33ESect-2.9 P-34ESect-2.9 P-35ESect-2.9 P-36ESect-2.9 P-37ESect-2.9 P-38ESect-2.9 P-39ESect-2.9 P-40ESect-2.9 P-41ESect-2.9 P-42ESect-2.R P-1CCSect-2.R P-2CCSect-2.R P-3CCSect-2.R P-4CCSect-2.R P-5CCSect-2.R P-6CCSect-2.R P-7CCSect-2.R P-8CCSect-2.R P-9CCSect-2.R P-10CCSect-2.R P-11CCSect-2.R P-12CCSect-2.R P-1TFQSect-2.R P-2TFQSect-2.R P-3TFQSect-2.R P-4TFQSect-2.R P-5TFQSect-2.R P-6TFQSect-2.R P-7TFQSect-2.R P-8TFQSect-2.R P-9TFQSect-2.R P-10TFQSect-2.R P-11TFQSect-2.R P-12TFQSect-2.R P-13TFQSect-2.R P-14TFQSect-2.R P-15TFQSect-2.R P-1ESect-2.R P-2ESect-2.R P-3ESect-2.R P-4ESect-2.R P-5ESect-2.R P-6ESect-2.R P-7ESect-2.R P-8ESect-2.R P-9ESect-2.R P-10ESect-2.R P-11ESect-2.R P-12ESect-2.R P-13ESect-2.R P-14ESect-2.R P-15ESect-2.R P-16ESect-2.R P-17ESect-2.R P-18ESect-2.R P-19ESect-2.R P-20ESect-2.R P-21ESect-2.R P-22ESect-2.R P-23ESect-2.R P-24ESect-2.R P-25ESect-2.R P-26ESect-2.R P-27ESect-2.R P-28ESect-2.R P-29ESect-2.R P-30ESect-2.R P-31ESect-2.R P-32ESect-2.R P-33ESect-2.R P-34ESect-2.R P-35ESect-2.R P-36ESect-2.R P-37ESect-2.R P-38ESect-2.R P-39ESect-2.R P-40ESect-2.R P-41ESect-2.R P-42ESect-2.R P-43ESect-2.R P-44ESect-2.R P-45ESect-2.R P-46ESect-2.R P-47ESect-2.R P-48ESect-2.R P-49ESect-2.R P-50ESect-2.R P-51ESect-2.R P-52ESect-2.R P-53ESect-2.R P-54ESect-2.R P-55ESect-2.R P-56ESect-2.R P-57ESect-2.R P-58ESect-2.R P-59ESect-2.R P-60ESect-2.R P-61ESect-2.R P-62ESect-2.R P-63ESect-2.R P-64ESect-2.R P-65ESect-2.R P-66ESect-2.R P-67ESect-2.R P-68ESect-2.R P-69ESect-2.R P-70ESect-2.R P-71ESect-2.R P-72ESect-2.R P-73ESect-2.R P-74ESect-2.R P-75ESect-2.R P-76ESect-2.R P-77ESect-2.R P-78ESect-2.R P-79ESect-2.R P-80ESect-2.R P-81ESect-2.R P-82ESect-2.R P-83ESect-2.R P-84ESect-2.R P-85ESect-2.R P-86ESect-2.R P-87ESect-2.R P-88ESect-2.R P-89ESect-2.R P-90ESect-2.R P-91ESect-2.R P-92ESect-2.P P-1PSect-2.P P-2PSect-2.P P-3PSect-2.P P-4PSect-2.P P-5PSect-2.P P-6PSect-2.P P-7PSect-2.P P-8PSect-2.P P-9PSect-2.P P-10PSect-2.P P-11PSect-2.P P-12PSect-2.P P-13PSect-2.P P-14PSect-2.P P-15PSect-2.P P-16PSect-2.P P-17PSect-2.P P-18PSect-2.P P-19PSect-2.P P-20PSect-2.P P-21PSect-2.P P-22PSect-2.P P-23PSect-2.P P-24PSect-2.P P-25PSect-2.P P-26PSect-2.P P-27PSect-2.P P-28P

Finite Mathematics and Applied Calculus (MindTap Course List)

Calculus: Early Transcendental Functions

Calculus: An Applied Approach (MindTap Course List)

Precalculus: Mathematics for Calculus (Standalone Book)

Applied Calculus

Single Variable Calculus: Early Transcendentals, Volume I

Multivariable Calculus

Calculus: Early Transcendentals

Essentials Of Statistics

Essentials of Statistics for The Behavioral Sciences (MindTap Course List)

Statistics for The Behavioral Sciences (MindTap Course List)

Single Variable Calculus

Applied Calculus for the Managerial, Life, and Social Sciences: A Brief Approach

Finite Mathematics

Understanding Basic Statistics

Intermediate Algebra

Elementary Technical Mathematics

Elementary Geometry For College Students, 7e

Probability and Statistics for Engineering and the Sciences

Mathematical Excursions (MindTap Course List)

Mathematical Applications for the Management, Life, and Social Sciences

Single Variable Calculus: Early Transcendentals

Calculus of a Single Variable

Trigonometry (MindTap Course List)

Elements Of Modern Algebra

Contemporary Mathematics for Business & Consumers

Study Guide for Stewart's Single Variable Calculus: Early Transcendentals, 8th

Study Guide for Stewart's Multivariable Calculus, 8th

Calculus: Early Transcendental Functions (MindTap Course List)

Finite Mathematics for the Managerial, Life, and Social Sciences

Elementary Geometry for College Students

Multivariable Calculus

Calculus (MindTap Course List)

Research Methods for the Behavioral Sciences (MindTap Course List)

College Algebra (MindTap Course List)

Mathematics For Machine Technology

Research Methods for the Behavioral Sciences (MindTap Course List)

Statistics for Business & Economics, Revised (MindTap Course List)

Introduction To Statistics And Data Analysis

STATISTICS F/BUSINESS+ECONOMICS-TEXT

Mathematics: A Practical Odyssey