9.15 problem 1870

Internal problem ID [10193]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 8, system of first order odes
Problem number: 1870.
ODE order: 1.
ODE degree: 1.

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

Solution by Maple

Time used: 0.094 (sec). Leaf size: 47

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

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

Solution by Mathematica

Time used: 0.19 (sec). Leaf size: 71

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

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