15.3 problem 12

Internal problem ID [5446]

Book: Schaums Outline. Theory and problems of Differential Equations, 1st edition. Frank Ayres. McGraw Hill 1952
Section: Chapter 21. System of simultaneous linear equations. Supplemetary problems. Page 163
Problem number: 12.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x^{\prime }\left (t \right )&=4-5 x \left (t \right )-y \left (t \right )-{\mathrm e}^{t}\\ y^{\prime }\left (t \right )&=2 x \left (t \right )-3 y \left (t \right )+{\mathrm e}^{t}-1 \end {align*}

Solution by Maple

Time used: 0.047 (sec). Leaf size: 72

dsolve([diff(x(t),t)+x(t)+2*diff(y(t),t)+7*y(t)=exp(t)+2,-2*x(t)+diff(y(t),t)+3*y(t)=exp(t)-1],[x(t), y(t)], singsol=all)
 

\begin{align*} x \left (t \right ) = -\frac {{\mathrm e}^{-4 t} \sin \left (t \right ) c_{2}}{2}+\frac {{\mathrm e}^{-4 t} \cos \left (t \right ) c_{2}}{2}-\frac {{\mathrm e}^{-4 t} \cos \left (t \right ) c_{1}}{2}-\frac {{\mathrm e}^{-4 t} \sin \left (t \right ) c_{1}}{2}-\frac {5 \,{\mathrm e}^{t}}{26}+\frac {13}{17} y \left (t \right ) = {\mathrm e}^{-4 t} \sin \left (t \right ) c_{2} +{\mathrm e}^{-4 t} \cos \left (t \right ) c_{1} +\frac {3}{17}+\frac {2 \,{\mathrm e}^{t}}{13} \end{align*}

Solution by Mathematica

Time used: 0.239 (sec). Leaf size: 79

DSolve[{x'[t]+x[t]+2*y'[t]+7*y[t]==Exp[t]+2,-2*x[t]+y'[t]+3*y[t]==Exp[t]-1},{x[t],y[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} x(t)\to -\frac {5 e^t}{26}+c_1 e^{-4 t} \cos (t)-(c_1+c_2) e^{-4 t} \sin (t)+\frac {13}{17} y(t)\to \frac {2 e^t}{13}+c_2 e^{-4 t} \cos (t)+(2 c_1+c_2) e^{-4 t} \sin (t)+\frac {3}{17} \end{align*}