Calculus 8th Edition

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

Chapter 17 - Second-Order Differential Equations - 17.1 Second-Order Linear Equations - 17.1 Exercises - Page 1200: 31

Answer

Since we cannot determine the value of $c_{2}$, we can say that the given problem has no solution.

Work Step by Step

$y''+4y'+20y=0$ Use auxiliary equation $r^{2}+4r+20=0$ $r=\frac{-4±\sqrt ((4^{2}-4(1)(20))}{2(1)}$ $r=\frac{-4±\sqrt (-64)}{2}$ $r_{1}=-2+4i$ $r_{2}=-2-4i$ $r_{1}=α+βi$ $r_{2}=α-βi$ $α=-2$ $β=4$ $y=e^{αx}(c_{1}cosβx+c_{2}sinβx$ $y=e^{-2x}(c_{1}cos4x+c_{2}sin4x$ $y(0)=1$ $1=e^{-2(0)}(c_{1}cos4(0)+c_{2}sin4(0)$ $1=c_{1}(1)+c_{2}(0)$ $c_{1}=1$ $y(\pi)=2$ $2=e^{-2(\pi)}(c_{1}cos4(\pi)+c_{2}sin4(\pi)$ $2=e^{-2\pi}[c_{1}(1)+c_{2}(0)]$ $c_{1}=\frac{2}{e^{-2\pi}}$ Since we cannot determine the value of $c_{2}$, we can say that the given problem has no solution.
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.