10.2 problem 2

Internal problem ID [13077]

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: 2.
ODE order: 1.
ODE degree: 1.

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

Solution by Maple

Time used: 0.016 (sec). Leaf size: 36

dsolve([diff(x(t),t)=-4*x(t)-2*y(t),diff(y(t),t)=-x(t)-3*y(t)],singsol=all)
 

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

Solution by Mathematica

Time used: 0.009 (sec). Leaf size: 71

DSolve[{x'[t]==-4*x[t]-2*y[t],y'[t]==-x[t]-3*y[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} x(t)\to \frac {1}{3} e^{-5 t} \left (c_1 \left (e^{3 t}+2\right )-2 c_2 \left (e^{3 t}-1\right )\right ) \\ y(t)\to \frac {1}{3} e^{-5 t} \left (c_1 \left (-e^{3 t}\right )+2 c_2 e^{3 t}+c_1+c_2\right ) \\ \end{align*}