9.9 problem 1864

Internal problem ID [10187]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 8, system of first order odes
Problem number: 1864.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x^{\prime }\left (t \right )&=-5 x \left (t \right )-2 y \left (t \right )\\ y^{\prime }\left (t \right )&=x \left (t \right )-7 y \left (t \right ) \end {align*}

Solution by Maple

Time used: 0.016 (sec). Leaf size: 46

dsolve({diff(x(t),t)=-5*x(t)-2*y(t),diff(y(t),t)=x(t)-7*y(t)},singsol=all)
 

\begin{align*} x \left (t \right ) &= {\mathrm e}^{-6 t} \left (c_{1} \sin \left (t \right )+c_{2} \cos \left (t \right )\right ) \\ y \left (t \right ) &= \frac {{\mathrm e}^{-6 t} \left (c_{1} \sin \left (t \right )+c_{2} \sin \left (t \right )-c_{1} \cos \left (t \right )+c_{2} \cos \left (t \right )\right )}{2} \\ \end{align*}

Solution by Mathematica

Time used: 0.009 (sec). Leaf size: 52

DSolve[{x'[t]==-5*x[t]-2*y[t],y'[t]==x[t]-7*y[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} x(t)\to e^{-6 t} (c_1 \cos (t)+(c_1-2 c_2) \sin (t)) \\ y(t)\to e^{-6 t} (c_2 \cos (t)+(c_1-c_2) \sin (t)) \\ \end{align*}