BuyFindarrow_forward

Calculus: Early Transcendentals

8th Edition
James Stewart
ISBN: 9781285741550

Solutions

Chapter
Section
BuyFindarrow_forward

Calculus: Early Transcendentals

8th Edition
James Stewart
ISBN: 9781285741550
Textbook Problem

Find the local maximum and minimum values and saddle points of the function. If you have three-dimensional graphing software, graph the function with a domain and viewpoint that reveal all the important aspects of the function.

53. f(x, y) = 3xyx2yxy2

To determine

To find: The local maximum, local minimum and saddle point of the function, f(x,y)=3xyx2yxy2 .

Explanation

Second Derivative Test:

“Suppose the second partial derivatives of f are continuous on a disk with center (a,b) , and suppose that fx(a,b)=0 and fy(a,b)=0 (that is (a,b) is a critical point of f). Let

D=D(a,b)=fxx(a,b)fyy(a,b)[fxy(a,b)]2

(a) If D>0 and fxx(a,b)>0 , then f(a,b) is a local minimum.

(b) If D>0 and fxx(a,b)<0 , then f(a,b) is a local maximum.

(c) If D<0 , then f(a,b) is not a local maximum or minimum and it is called a saddle point”.

Calculation:

The given function is, f(x,y)=3xyx2yxy2 .

Take the partial derivative in the given function with respect to x and obtain fx .

fx=x(3xyx2yxy2)=x(3xy)x(x2y)x(xy2)=3y(1)y(2x)y2(1)=3y2xyy2

Thus, fx=3y2xyy2 (1)

Take the partial derivative in the given with respect to y and obtain fy .

fy=y(3xyx2yxy2)=y(3xy)y(x2y)y(xy2)=3x(1)x2(1)x(2y)=3xx22xy

Thus, fy=3xx22xy (2)

Set the above derivative to 0 and solve the equations (1) and (2) to get the values of x and y.

From the equation (1),

3y2xyy2=0y(32xy)=0y=0,y=32x

Substitute y=32x in the equation (2) and obtain the value of x.

3xx22x(32x)=03xx26x+4x2=03x2=3xx=1

Substitute x=1 in the equation y=32x and obtain y value.

y=32(1)=32=1

Substitute y=0 in the equation (2) and obtain x value.

3xx22x(0)=03xx2=0x(3x)=0x=0,x=3

Substitute x=0 in the equation y=32x and obtain y value.

y=32(0)=30=3

Thus, the critical points are, (0,0) , (3,0) , (0,3) and (1,1) .

Take the partial derivative of the equation (1) with respect to x and obtain fxx .

2fx2=x(3y2xyy2)=x(3y)x(2xy)x(y2)=02y(1)0=2y

Hence, 2fx2=2y .

Take the partial derivative of the equation (2) with respect to y and obtain fyy

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Chapter 14 Solutions

Show all chapter solutions add
Sect-14.1 P-11ESect-14.1 P-12ESect-14.1 P-13ESect-14.1 P-14ESect-14.1 P-15ESect-14.1 P-16ESect-14.1 P-17ESect-14.1 P-18ESect-14.1 P-19ESect-14.1 P-20ESect-14.1 P-21ESect-14.1 P-22ESect-14.1 P-23ESect-14.1 P-24ESect-14.1 P-25ESect-14.1 P-26ESect-14.1 P-27ESect-14.1 P-28ESect-14.1 P-29ESect-14.1 P-30ESect-14.1 P-31ESect-14.1 P-32ESect-14.1 P-33ESect-14.1 P-34ESect-14.1 P-35ESect-14.1 P-36ESect-14.1 P-37ESect-14.1 P-38ESect-14.1 P-39ESect-14.1 P-40ESect-14.1 P-41ESect-14.1 P-42ESect-14.1 P-43ESect-14.1 P-44ESect-14.1 P-45ESect-14.1 P-46ESect-14.1 P-47ESect-14.1 P-48ESect-14.1 P-49ESect-14.1 P-50ESect-14.1 P-51ESect-14.1 P-52ESect-14.1 P-53ESect-14.1 P-54ESect-14.1 P-55ESect-14.1 P-56ESect-14.1 P-57ESect-14.1 P-58ESect-14.1 P-59ESect-14.1 P-60ESect-14.1 P-61ESect-14.1 P-62ESect-14.1 P-63ESect-14.1 P-64ESect-14.1 P-65ESect-14.1 P-66ESect-14.1 P-67ESect-14.1 P-68ESect-14.1 P-69ESect-14.1 P-70ESect-14.1 P-71ESect-14.1 P-72ESect-14.1 P-73ESect-14.1 P-74ESect-14.1 P-75ESect-14.1 P-76ESect-14.1 P-77ESect-14.1 P-78ESect-14.1 P-79ESect-14.1 P-80ESect-14.1 P-81ESect-14.2 P-1ESect-14.2 P-2ESect-14.2 P-3ESect-14.2 P-4ESect-14.2 P-5ESect-14.2 P-6ESect-14.2 P-7ESect-14.2 P-8ESect-14.2 P-9ESect-14.2 P-10ESect-14.2 P-11ESect-14.2 P-12ESect-14.2 P-13ESect-14.2 P-14ESect-14.2 P-15ESect-14.2 P-16ESect-14.2 P-17ESect-14.2 P-18ESect-14.2 P-19ESect-14.2 P-20ESect-14.2 P-21ESect-14.2 P-22ESect-14.2 P-23ESect-14.2 P-24ESect-14.2 P-25ESect-14.2 P-26ESect-14.2 P-27ESect-14.2 P-28ESect-14.2 P-29ESect-14.2 P-30ESect-14.2 P-31ESect-14.2 P-32ESect-14.2 P-33ESect-14.2 P-34ESect-14.2 P-35ESect-14.2 P-36ESect-14.2 P-37ESect-14.2 P-38ESect-14.2 P-39ESect-14.2 P-40ESect-14.2 P-41ESect-14.2 P-42ESect-14.2 P-43ESect-14.2 P-44ESect-14.2 P-45ESect-14.2 P-46ESect-14.3 P-1ESect-14.3 P-2ESect-14.3 P-3ESect-14.3 P-4ESect-14.3 P-5ESect-14.3 P-6ESect-14.3 P-7ESect-14.3 P-8ESect-14.3 P-9ESect-14.3 P-10ESect-14.3 P-11ESect-14.3 P-12ESect-14.3 P-13ESect-14.3 P-14ESect-14.3 P-15ESect-14.3 P-16ESect-14.3 P-17ESect-14.3 P-18ESect-14.3 P-19ESect-14.3 P-20ESect-14.3 P-21ESect-14.3 P-22ESect-14.3 P-23ESect-14.3 P-24ESect-14.3 P-25ESect-14.3 P-26ESect-14.3 P-27ESect-14.3 P-28ESect-14.3 P-29ESect-14.3 P-30ESect-14.3 P-31ESect-14.3 P-32ESect-14.3 P-33ESect-14.3 P-34ESect-14.3 P-35ESect-14.3 P-36ESect-14.3 P-37ESect-14.3 P-38ESect-14.3 P-39ESect-14.3 P-40ESect-14.3 P-41ESect-14.3 P-42ESect-14.3 P-43ESect-14.3 P-44ESect-14.3 P-45ESect-14.3 P-46ESect-14.3 P-47ESect-14.3 P-48ESect-14.3 P-49ESect-14.3 P-50ESect-14.3 P-51ESect-14.3 P-52ESect-14.3 P-53ESect-14.3 P-54ESect-14.3 P-55ESect-14.3 P-56ESect-14.3 P-57ESect-14.3 P-58ESect-14.3 P-59ESect-14.3 P-60ESect-14.3 P-61ESect-14.3 P-62ESect-14.3 P-63ESect-14.3 P-64ESect-14.3 P-65ESect-14.3 P-66ESect-14.3 P-67ESect-14.3 P-68ESect-14.3 P-69ESect-14.3 P-70ESect-14.3 P-71ESect-14.3 P-72ESect-14.3 P-73ESect-14.3 P-74ESect-14.3 P-75ESect-14.3 P-76ESect-14.3 P-77ESect-14.3 P-78ESect-14.3 P-79ESect-14.3 P-80ESect-14.3 P-81ESect-14.3 P-82ESect-14.3 P-83ESect-14.3 P-84ESect-14.3 P-85ESect-14.3 P-86ESect-14.3 P-87ESect-14.3 P-88ESect-14.3 P-89ESect-14.3 P-90ESect-14.3 P-91ESect-14.3 P-92ESect-14.3 P-93ESect-14.3 P-94ESect-14.3 P-95ESect-14.3 P-96ESect-14.3 P-97ESect-14.3 P-98ESect-14.3 P-99ESect-14.3 P-100ESect-14.3 P-101ESect-14.3 P-102ESect-14.3 P-103ESect-14.3 P-104ESect-14.4 P-1ESect-14.4 P-2ESect-14.4 P-3ESect-14.4 P-4ESect-14.4 P-5ESect-14.4 P-6ESect-14.4 P-7ESect-14.4 P-8ESect-14.4 P-11ESect-14.4 P-12ESect-14.4 P-13ESect-14.4 P-14ESect-14.4 P-15ESect-14.4 P-16ESect-14.4 P-17ESect-14.4 P-18ESect-14.4 P-19ESect-14.4 P-20ESect-14.4 P-21ESect-14.4 P-22ESect-14.4 P-23ESect-14.4 P-24ESect-14.4 P-25ESect-14.4 P-26ESect-14.4 P-27ESect-14.4 P-28ESect-14.4 P-29ESect-14.4 P-30ESect-14.4 P-31ESect-14.4 P-32ESect-14.4 P-33ESect-14.4 P-34ESect-14.4 P-35ESect-14.4 P-36ESect-14.4 P-37ESect-14.4 P-38ESect-14.4 P-39ESect-14.4 P-40ESect-14.4 P-41ESect-14.4 P-42ESect-14.4 P-43ESect-14.4 P-44ESect-14.4 P-45ESect-14.4 P-46ESect-14.5 P-1ESect-14.5 P-2ESect-14.5 P-3ESect-14.5 P-4ESect-14.5 P-5ESect-14.5 P-6ESect-14.5 P-7ESect-14.5 P-8ESect-14.5 P-9ESect-14.5 P-10ESect-14.5 P-11ESect-14.5 P-12ESect-14.5 P-13ESect-14.5 P-14ESect-14.5 P-15ESect-14.5 P-16ESect-14.5 P-17ESect-14.5 P-18ESect-14.5 P-19ESect-14.5 P-20ESect-14.5 P-21ESect-14.5 P-22ESect-14.5 P-23ESect-14.5 P-24ESect-14.5 P-25ESect-14.5 P-26ESect-14.5 P-27ESect-14.5 P-28ESect-14.5 P-29ESect-14.5 P-30ESect-14.5 P-31ESect-14.5 P-32ESect-14.5 P-33ESect-14.5 P-34ESect-14.5 P-35ESect-14.5 P-36ESect-14.5 P-37ESect-14.5 P-38ESect-14.5 P-39ESect-14.5 P-40ESect-14.5 P-41ESect-14.5 P-42ESect-14.5 P-43ESect-14.5 P-44ESect-14.5 P-45ESect-14.5 P-46ESect-14.5 P-47ESect-14.5 P-48ESect-14.5 P-49ESect-14.5 P-50ESect-14.5 P-51ESect-14.5 P-53ESect-14.5 P-55ESect-14.5 P-56ESect-14.5 P-57ESect-14.5 P-58ESect-14.5 P-59ESect-14.6 P-1ESect-14.6 P-2ESect-14.6 P-3ESect-14.6 P-4ESect-14.6 P-5ESect-14.6 P-6ESect-14.6 P-7ESect-14.6 P-8ESect-14.6 P-9ESect-14.6 P-10ESect-14.6 P-11ESect-14.6 P-12ESect-14.6 P-13ESect-14.6 P-14ESect-14.6 P-15ESect-14.6 P-16ESect-14.6 P-17ESect-14.6 P-18ESect-14.6 P-19ESect-14.6 P-20ESect-14.6 P-21ESect-14.6 P-22ESect-14.6 P-23ESect-14.6 P-24ESect-14.6 P-25ESect-14.6 P-26ESect-14.6 P-27ESect-14.6 P-28ESect-14.6 P-29ESect-14.6 P-30ESect-14.6 P-31ESect-14.6 P-32ESect-14.6 P-33ESect-14.6 P-34ESect-14.6 P-35ESect-14.6 P-36ESect-14.6 P-37ESect-14.6 P-38ESect-14.6 P-39ESect-14.6 P-40ESect-14.6 P-41ESect-14.6 P-42ESect-14.6 P-43ESect-14.6 P-44ESect-14.6 P-45ESect-14.6 P-46ESect-14.6 P-47ESect-14.6 P-48ESect-14.6 P-49ESect-14.6 P-50ESect-14.6 P-51ESect-14.6 P-52ESect-14.6 P-53ESect-14.6 P-54ESect-14.6 P-55ESect-14.6 P-56ESect-14.6 P-57ESect-14.6 P-58ESect-14.6 P-59ESect-14.6 P-60ESect-14.6 P-61ESect-14.6 P-62ESect-14.6 P-63ESect-14.6 P-64ESect-14.6 P-65ESect-14.6 P-66ESect-14.6 P-67ESect-14.6 P-68ESect-14.6 P-69ESect-14.6 P-70ESect-14.7 P-1ESect-14.7 P-2ESect-14.7 P-3ESect-14.7 P-4ESect-14.7 P-5ESect-14.7 P-6ESect-14.7 P-7ESect-14.7 P-8ESect-14.7 P-9ESect-14.7 P-10ESect-14.7 P-11ESect-14.7 P-12ESect-14.7 P-13ESect-14.7 P-14ESect-14.7 P-15ESect-14.7 P-16ESect-14.7 P-17ESect-14.7 P-18ESect-14.7 P-19ESect-14.7 P-20ESect-14.7 P-21ESect-14.7 P-22ESect-14.7 P-23ESect-14.7 P-24ESect-14.7 P-25ESect-14.7 P-26ESect-14.7 P-27ESect-14.7 P-28ESect-14.7 P-29ESect-14.7 P-30ESect-14.7 P-31ESect-14.7 P-32ESect-14.7 P-33ESect-14.7 P-34ESect-14.7 P-35ESect-14.7 P-36ESect-14.7 P-37ESect-14.7 P-38ESect-14.7 P-39ESect-14.7 P-40ESect-14.7 P-41ESect-14.7 P-42ESect-14.7 P-43ESect-14.7 P-44ESect-14.7 P-45ESect-14.7 P-46ESect-14.7 P-47ESect-14.7 P-48ESect-14.7 P-49ESect-14.7 P-50ESect-14.7 P-51ESect-14.7 P-52ESect-14.7 P-53ESect-14.7 P-54ESect-14.7 P-55ESect-14.7 P-56ESect-14.7 P-57ESect-14.7 P-58ESect-14.7 P-59ESect-14.7 P-60ESect-14.8 P-1ESect-14.8 P-2ESect-14.8 P-3ESect-14.8 P-4ESect-14.8 P-5ESect-14.8 P-6ESect-14.8 P-7ESect-14.8 P-8ESect-14.8 P-9ESect-14.8 P-10ESect-14.8 P-11ESect-14.8 P-12ESect-14.8 P-13ESect-14.8 P-14ESect-14.8 P-15ESect-14.8 P-16ESect-14.8 P-17ESect-14.8 P-18ESect-14.8 P-19ESect-14.8 P-20ESect-14.8 P-21ESect-14.8 P-22ESect-14.8 P-23ESect-14.8 P-24ESect-14.8 P-25ESect-14.8 P-27ESect-14.8 P-28ESect-14.8 P-29ESect-14.8 P-30ESect-14.8 P-31ESect-14.8 P-32ESect-14.8 P-33ESect-14.8 P-34ESect-14.8 P-35ESect-14.8 P-36ESect-14.8 P-37ESect-14.8 P-38ESect-14.8 P-39ESect-14.8 P-40ESect-14.8 P-41ESect-14.8 P-42ESect-14.8 P-43ESect-14.8 P-44ESect-14.8 P-45ESect-14.8 P-46ESect-14.8 P-49ESect-14.8 P-50ECh-14 P-1RCCCh-14 P-2RCCCh-14 P-3RCCCh-14 P-4RCCCh-14 P-5RCCCh-14 P-6RCCCh-14 P-7RCCCh-14 P-8RCCCh-14 P-9RCCCh-14 P-10RCCCh-14 P-11RCCCh-14 P-12RCCCh-14 P-13RCCCh-14 P-14RCCCh-14 P-15RCCCh-14 P-16RCCCh-14 P-17RCCCh-14 P-18RCCCh-14 P-19RCCCh-14 P-1RQCh-14 P-2RQCh-14 P-3RQCh-14 P-4RQCh-14 P-5RQCh-14 P-6RQCh-14 P-7RQCh-14 P-8RQCh-14 P-9RQCh-14 P-10RQCh-14 P-11RQCh-14 P-12RQCh-14 P-1RECh-14 P-2RECh-14 P-3RECh-14 P-4RECh-14 P-5RECh-14 P-6RECh-14 P-7RECh-14 P-8RECh-14 P-9RECh-14 P-10RECh-14 P-11RECh-14 P-12RECh-14 P-13RECh-14 P-14RECh-14 P-15RECh-14 P-16RECh-14 P-17RECh-14 P-18RECh-14 P-19RECh-14 P-20RECh-14 P-21RECh-14 P-22RECh-14 P-23RECh-14 P-24RECh-14 P-25RECh-14 P-26RECh-14 P-27RECh-14 P-28RECh-14 P-29RECh-14 P-30RECh-14 P-31RECh-14 P-32RECh-14 P-33RECh-14 P-34RECh-14 P-35RECh-14 P-36RECh-14 P-37RECh-14 P-38RECh-14 P-39RECh-14 P-40RECh-14 P-41RECh-14 P-42RECh-14 P-43RECh-14 P-44RECh-14 P-45RECh-14 P-46RECh-14 P-47RECh-14 P-48RECh-14 P-49RECh-14 P-50RECh-14 P-51RECh-14 P-52RECh-14 P-53RECh-14 P-54RECh-14 P-55RECh-14 P-56RECh-14 P-57RECh-14 P-58RECh-14 P-59RECh-14 P-60RECh-14 P-61RECh-14 P-62RECh-14 P-63RECh-14 P-64RECh-14 P-65RECh-14 P-1PCh-14 P-2PCh-14 P-3PCh-14 P-4PCh-14 P-5PCh-14 P-6PCh-14 P-7PCh-14 P-8P

Additional Math Solutions

Find more solutions based on key concepts

Show solutions add

Fill in the blanks. 9. a. The statement limxa+ f(x) = L is similar to the statement limxaf(x) = L, but here x i...

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

Perform the indicated operations: 12+2+306

Elementary Technical Mathematics

Prove the second law of exponents [see (15)].

Single Variable Calculus: Early Transcendentals

Sometimes, Always, or Never: The value of x2 in Newtons Method will be a closer approximation to the root than ...

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

Given that the points P(2,3) lies on the line 2x+ky+10=0, find k.

Finite Mathematics for the Managerial, Life, and Social Sciences