Calculus 8th Edition

Published by Cengage
ISBN 10: 1285740629
ISBN 13: 978-1-28574-062-1

Chapter 15 - Multiple Integrals - 15.4 Applications of Double Integrals - 15.4 Exercises - Page 1065: 7

Answer

$m$ = $\frac{8k}{15}$ $(0,\frac{4}{7})$

Work Step by Step

$m$ = $\int_{-1}^1\int_0^{1-x^2}kydydx$ $m$ = $\frac{k}{2}\int_{-1}^1[y^2]|_0^{1-x^2}dx$ $m$ = $\frac{k}{2}\int_{-1}^1[1-2x^2+x^4]dx$ $m$ = $\frac{k}{2}[x-\frac{2x^3}{3}+\frac{x^5}{5}]_{-1}^1$ $m$ = $\frac{8k}{15}$ $x̄$ = $\frac{1}{m}\int_{-1}^1\int_0^{1-x^2}kxydydx$ $x̄$ = $\frac{15}{8}\int_{-1}^1\int_0^{1-x^2}xydydx$ $x̄$ = $\frac{15}{8}\int_{-1}^1[\frac{xy^2}{2}]|_0^{1-x^2}dx$ $x̄$ = $\frac{15}{16}\int_{-1}^1(x-2x^3+x^5)dx$ $x̄$ = $\frac{15}{16}[\frac{x^2}{2}-\frac{x^4}{2}+\frac{x^6}{6}]_{-1}^1$ $x̄$ = $0$ $ȳ$ = $\frac{1}{m}\int_{-1}^1\int_0^{1-x^2}ky^2dydx$ $ȳ$ = $\frac{15}{8}\int_{-1}^1\int_0^{1-x^2}y^2dydx$ $ȳ$ = $\frac{15}{8}\int_{-1}^1[\frac{y^3}{3}]_0^{1-x^2}dx$ $ȳ$ = $\frac{5}{8}\int_{-1}^1(1-3x^2+3x^4-x^6)dx$ $ȳ$ = $\frac{5}{8}[x-x^3+\frac{3x^5}{5}-\frac{x^7}{7}]_{-1}^1$ $ȳ$ = $\frac{4}{7}$
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.