Differential Equations and Linear Algebra (4th Edition)

Published by Pearson
ISBN 10: 0-32196-467-5
ISBN 13: 978-0-32196-467-0

Chapter 1 - First-Order Differential Equations - 1.2 Basic Ideas and Terminology - Problems - Page 22: 43

Answer

$y=\frac{2e^2}{e-1}(x-1)-2x^2 \ln (x)-\frac{2e^2}{e-1}$

Work Step by Step

Integrate the function to turn $y''$ into $y'$. $$y''=-2(3+2\ln (x))$$ $$y'=-2(x+2x\ln (x))+C_1$$ Integrate once again to turn $y'$ into $y$. $$y=x(C_1-2x\ln (x))+C_2$$ Solve for the initial values. $$y(1)=(C_1-2\ln (1))+C_2=0$$ $$C_1+C_2=0$$ $$y(e)=e(C_1-2e\ln (e))+C_2$$ $$C_1e-2e^2+C_2=0$$ Then we have the system: $C_1+C_2=0$ $C_1e-2e^2+C_2=0$ Using substitution: $C_1=-C_2$ $C_1e-2e^2-C_1=0$ then $C_1=\frac{2e^2}{e-1}$ $C_2=-\frac{2e^2}{e-1}$ Substitute these constant values to get $y=\frac{2e^2}{e-1}(x-1)-2x^2 \ln (x)-\frac{2e^2}{e-1}$
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.