Calculus with Applications (10th Edition)

Published by Pearson
ISBN 10: 0321749006
ISBN 13: 978-0-32174-900-0

Chapter 7 - Integration - 7.5 The Area Between Two Curves - 7.5 Exercises - Page 405: 20

Answer

$$A = \frac{1}{6}$$

Work Step by Step

$$\eqalign{ & y = {x^5} - 2\ln \left( {x + 5} \right),\,\,\,\,\,\,y = {x^3} - 2\ln \left( {x + 5} \right) \cr & {\text{Find the points of intersection of the graphs equating the functions}} \cr & {x^5} - 2\ln \left( {x + 5} \right) = {x^3} - 2\ln \left( {x + 5} \right) \cr & {x^5} = {x^3} \cr & {x^5} - {x^3} = 0 \cr & {x^3}\left( {{x^2} - 1} \right) \cr & {x^3}\left( {x + 1} \right)\left( {x - 1} \right) \cr & x = 0,\,\,x = - 1,\,\,\,x = 1 \cr & {\text{Then with the critical value we have the intervals }}\left( { - 1,0} \right){\text{ and }}\left( {0,1} \right) \cr & {\text{For the interval }}\left( { - 1,0} \right){\text{ we have that }}{x^5} - 2\ln \left( {x + 5} \right) > {x^3} - 2\ln \left( {x + 5} \right) \cr & {\text{For the interval }}\left( {0,1} \right){\text{ we have that }}{x^3} - 2\ln \left( {x + 5} \right) > {x^5} - 2\ln \left( {x + 5} \right) \cr & \cr & {\text{The area between the curves is given by}}: \cr & A = \int_{ - 1}^0 {\left( {{x^5} - 2\ln \left( {x + 5} \right) - {x^3} + 2\ln \left( {x + 5} \right)} \right)} dx \cr & + \int_0^1 {\left( {{x^3} - 2\ln \left( {x + 5} \right) - {x^5} + 2\ln \left( {x + 5} \right)} \right)} dx \cr & \cr & A = \int_{ - 1}^0 {\left( {{x^5} - {x^3}} \right)} dx + \int_0^1 {\left( {{x^3} - {x^5}} \right)} dx \cr & {\text{Integrating}} \cr & A = \left( {\frac{1}{6}{x^6} - \frac{1}{4}{x^4}} \right)_{ - 1}^0 + \left( {\frac{1}{4}{x^4} - \frac{1}{6}{x^6}} \right)_0^1 \cr & A = \left( {\frac{1}{6}{{\left( 0 \right)}^6} - \frac{1}{4}{{\left( 0 \right)}^4}} \right) - \left( {\frac{1}{6}{{\left( { - 1} \right)}^6} - \frac{1}{4}{{\left( { - 1} \right)}^4}} \right) \cr & + \left( {\frac{1}{4}{{\left( 1 \right)}^4} - \frac{1}{6}{{\left( 1 \right)}^6}} \right) - \left( {\frac{1}{4}{{\left( 0 \right)}^4} - \frac{1}{6}{{\left( 0 \right)}^6}} \right) \cr & \cr & A = \left( 0 \right) - \left( {\frac{1}{6} - \frac{1}{4}} \right) + \left( {\frac{1}{4} - \frac{1}{6}} \right) - \left( 0 \right) \cr & A = \frac{1}{6} \cr} $$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.