Internal problem ID [13085]
Book: DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th
edition. Brooks/Cole. Boston, USA. 2012
Section: Chapter 3. Linear Systems. Exercises section 3.2. page 277
Problem number: 10.
ODE order: 1.
ODE degree: 1.
Solve \begin {align*} x^{\prime }\left (t \right )&=-x \left (t \right )-2 y\\ y^{\prime }&=x \left (t \right )-4 y \end {align*}
✓ Solution by Maple
Time used: 0.031 (sec). Leaf size: 35
dsolve([diff(x(t),t)=-x(t)-2*y(t),diff(y(t),t)=x(t)-4*y(t)],singsol=all)
\begin{align*} x \left (t \right ) &= c_{1} {\mathrm e}^{-2 t}+c_{2} {\mathrm e}^{-3 t} \\ y \left (t \right ) &= \frac {c_{1} {\mathrm e}^{-2 t}}{2}+c_{2} {\mathrm e}^{-3 t} \\ \end{align*}
✓ Solution by Mathematica
Time used: 0.005 (sec). Leaf size: 58
DSolve[{x'[t]==-x[t]-2*y[t],y'[t]==x[t]-4*y[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
\begin{align*} x(t)\to e^{-3 t} \left (c_1 \left (2 e^t-1\right )-2 c_2 \left (e^t-1\right )\right ) \\ y(t)\to e^{-3 t} \left (c_1 \left (e^t-1\right )-c_2 \left (e^t-2\right )\right ) \\ \end{align*}