9.25 problem Problem 25

Internal problem ID [2289]

Book: Differential equations and linear algebra, Stephen W. Goode and Scott A Annin. Fourth edition, 2015
Section: Chapter 8, Linear differential equations of order n. Section 8.7, The Variation of Parameters Method. page 556
Problem number: Problem 25.
ODE order: 2.
ODE degree: 1.

CAS Maple gives this as type [[_2nd_order, _linear, _nonhomogeneous]]

Solve \begin {gather*} \boxed {y^{\prime \prime }+y^{\prime }-2 y-F \relax (x )=0} \end {gather*}

Solution by Maple

Time used: 0.007 (sec). Leaf size: 47

dsolve(diff(y(x),x$2)+diff(y(x),x)-2*y(x)=F(x),y(x), singsol=all)
 

\[ y \relax (x ) = c_{2} {\mathrm e}^{x}+{\mathrm e}^{-2 x} c_{1}+\frac {\left (\left (\int {\mathrm e}^{-x} F \relax (x )d x \right ) {\mathrm e}^{3 x}-\left (\int F \relax (x ) {\mathrm e}^{2 x}d x \right )\right ) {\mathrm e}^{-2 x}}{3} \]

Solution by Mathematica

Time used: 0.031 (sec). Leaf size: 62

DSolve[y''[x]+y'[x]-2*y[x]==F[x],y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to e^{-2 x} \left (\int _1^x-\frac {1}{3} e^{2 K[1]} F(K[1])dK[1]+c_1\right )+e^x \left (\int _1^x\frac {1}{3} e^{-K[2]} F(K[2])dK[2]+c_2\right ) \\ \end{align*}