Elementary Differential Equations and Boundary Value Problems 9th Edition

Published by Wiley
ISBN 10: 0-47038-334-8
ISBN 13: 978-0-47038-334-6

Chapter 2 - First Order Differential Equations - 2.1 Linear Equations; Method of Integrating Factors - Problems - Page 39: 17

Answer

The solution of the initial value problem is $y=te^{2t}+2e^{2t}$.

Work Step by Step

By, comparing the differential equation with the linear form $y'+P(t)y=Q(t)$ We get, $P(t)=-2$ Thus, the integrating factor $u(t)=e^{\int -2\, dt}$ $\implies u(t)=e^{-2t+c}=e^{-2t}e^c$ Now multiply the equation by $u(t)$ on both sides. We get, $e^{-2t}e^cy'-2e^{-2t}e^cy=e^{-2t}e^c\cdot e^{2t}$ Now integrate on both sides We get, $ e^{-2t}y=\int e^{-2t}\cdot e^{2t}\,dt$ Now simplify as follows; $ e^{-2t}y=\int 1\,dt$ $\implies e^{-2t}y=t+c$ Substitute the initial condition $y(0)=2$ We get, $e^{0}2=0+c$ $\implies c=2$ Hence, the solution of the initial value problem is $y=te^{2t}+2e^{2t}$.
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.