9.4 problem 1859

Internal problem ID [9438]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 8, system of first order odes
Problem number: 1859.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x^{\prime }\relax (t )&=a x \relax (t )-y \relax (t )\\ y^{\prime }\relax (t )&=x \relax (t )+a y \relax (t ) \end {align*}

Solution by Maple

Time used: 0.078 (sec). Leaf size: 37

dsolve({diff(x(t),t)=a*x(t)-y(t),diff(y(t),t)=x(t)+a*y(t)},{x(t), y(t)}, singsol=all)
 

\[ x \relax (t ) = {\mathrm e}^{a t} \left (c_{1} \sin \relax (t )+c_{2} \cos \relax (t )\right ) \] \[ y \relax (t ) = {\mathrm e}^{a t} \left (\sin \relax (t ) c_{2}-\cos \relax (t ) c_{1}\right ) \]

Solution by Mathematica

Time used: 0.002 (sec). Leaf size: 43

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

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