Internal problem ID [11536]
Book: A First Course in Differential Equations by J. David Logan. Third Edition. Springer-Verlag,
NY. 2015.
Section: Chapter 4, Linear Systems. Exercises page 190
Problem number: 3(b).
ODE order: 1.
ODE degree: 1.
Solve \begin {align*} x^{\prime }&=x-y \left (t \right )\\ y^{\prime }\left (t \right )&=x+y \left (t \right ) \end {align*}
✓ Solution by Maple
Time used: 0.016 (sec). Leaf size: 34
dsolve([diff(x(t),t)=x(t)-y(t),diff(y(t),t)=x(t)+y(t)],singsol=all)
\begin{align*} x \left (t \right ) &= {\mathrm e}^{t} \left (c_{1} \sin \left (t \right )+c_{2} \cos \left (t \right )\right ) \\ y \left (t \right ) &= -{\mathrm e}^{t} \left (c_{1} \cos \left (t \right )-c_{2} \sin \left (t \right )\right ) \\ \end{align*}
✓ Solution by Mathematica
Time used: 0.003 (sec). Leaf size: 39
DSolve[{x'[t]==x[t]-y[t],y'[t]==x[t]+y[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
\begin{align*} x(t)\to e^t (c_1 \cos (t)-c_2 \sin (t)) \\ y(t)\to e^t (c_2 \cos (t)+c_1 \sin (t)) \\ \end{align*}