2.18 problem 18

Internal problem ID [4458]

Book: Fundamentals of Differential Equations. By Nagle, Saff and Snider. 9th edition. Boston. Pearson 2018.
Section: Chapter 2, First order differential equations. Section 2.3, Linear equations. Exercises. page 54
Problem number: 18.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [[_linear, `class A`]]

\[ \boxed {y^{\prime }+4 y-{\mathrm e}^{-x}=0} \] With initial conditions \begin {align*} \left [y \left (0\right ) = {\frac {4}{3}}\right ] \end {align*}

Solution by Maple

Time used: 0.0 (sec). Leaf size: 16

dsolve([diff(y(x),x)+4*y(x)-exp(-x)=0,y(0) = 4/3],y(x), singsol=all)
 

\[ y \left (x \right ) = \frac {\left ({\mathrm e}^{3 x}+3\right ) {\mathrm e}^{-4 x}}{3} \]

Solution by Mathematica

Time used: 0.047 (sec). Leaf size: 21

DSolve[{y'[x]+4*y[x]-Exp[-x]==0,{y[0]==4/3}},y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \frac {1}{3} e^{-4 x} \left (e^{3 x}+3\right ) \\ \end{align*}