Calculus, 10th Edition (Anton)

Published by Wiley
ISBN 10: 0-47064-772-8
ISBN 13: 978-0-47064-772-1

Chapter 7 - Principles Of Integral Evaluation - 7.8 Improper Integrals - Exercises Set 7.8 - Page 554: 22

Answer

$$ - \sqrt 8 $$

Work Step by Step

$$\eqalign{ & \int_{ - 3}^1 {\frac{{xdx}}{{\sqrt {9 - {x^2}} }}} \cr & {\text{The function is undefined for }}x = - 3,{\text{ so the integral can be repressented as}} \cr & \int_{ - 3}^1 {\frac{{xdx}}{{\sqrt {9 - {x^2}} }}} = \mathop {\lim }\limits_{k \to {0^ + }} \int_k^1 {\frac{{xdx}}{{\sqrt {9 - {x^2}} }}} \cr & {\text{Integrate}} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = - \mathop {\lim }\limits_{k \to {{\left( { - 3} \right)}^ + }} \left[ {\sqrt {9 - {x^2}} } \right]_k^1 \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = - \mathop {\lim }\limits_{k \to {{\left( { - 3} \right)}^ + }} \left[ {\sqrt {9 - {{\left( 1 \right)}^2}} - \sqrt {9 - {k^2}} } \right] \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = - \mathop {\lim }\limits_{k \to {{\left( { - 3} \right)}^ + }} \left[ {\sqrt 8 - \sqrt {9 - {k^2}} } \right] \cr & \,{\text{Calculate the limit when }}k \to {0^ + } \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = - \left[ {\sqrt 8 - \sqrt {9 - {{\left( { - 3} \right)}^2}} } \right] \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = - \sqrt 8 \cr & {\text{Then}}{\text{,}} \cr & \int_{ - 3}^1 {\frac{{xdx}}{{\sqrt {9 - {x^2}} }}} = - \sqrt 8 \cr} $$
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.