32.5 problem 829

Internal problem ID [15552]

Book: A book of problems in ordinary differential equations. M.L. KRASNOV, A.L. KISELYOV, G.I. MARKARENKO. MIR, MOSCOW. 1983
Section: Chapter 3 (Systems of differential equations). Section 23.3 dAlemberts method. Exercises page 243
Problem number: 829.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x^{\prime }\left (t \right )&=2 x \left (t \right )+4 y \left (t \right )+\cos \left (t \right )\\ y^{\prime }\left (t \right )&=-x \left (t \right )-2 y \left (t \right )+\sin \left (t \right ) \end {align*}

Solution by Maple

Time used: 0.031 (sec). Leaf size: 36

dsolve([diff(x(t),t)=2*x(t)+4*y(t)+cos(t),diff(y(t),t)=-x(t)-2*y(t)+sin(t)],singsol=all)
 

\begin{align*} x \left (t \right ) &= -2 \cos \left (t \right )-3 \sin \left (t \right )+c_{1} t +c_{2} \\ y \left (t \right ) &= 2 \sin \left (t \right )+\frac {c_{1}}{4}-\frac {c_{1} t}{2}-\frac {c_{2}}{2} \\ \end{align*}

Solution by Mathematica

Time used: 0.049 (sec). Leaf size: 46

DSolve[{x'[t]==2*x[t]+4*y[t]+Cos[t],y'[t]==-x[t]-2*y[t]+Sin[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
                                                                                    
                                                                                    
 

\begin{align*} x(t)\to -3 \sin (t)-2 \cos (t)+2 c_1 t+4 c_2 t+c_1 \\ y(t)\to 2 \sin (t)-(c_1+2 c_2) t+c_2 \\ \end{align*}