27.10 problem 38.10 (d)

Internal problem ID [14030]

Book: Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020
Section: Chapter 38. Systems of differential equations. A starting point. Additional Exercises. page 786
Problem number: 38.10 (d).
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x^{\prime }\left (t \right )&=-2 y \left (t \right )\\ y^{\prime }\left (t \right )&=8 x \left (t \right ) \end {align*}

Solution by Maple

Time used: 0.032 (sec). Leaf size: 36

dsolve([diff(x(t),t)=-2*y(t),diff(y(t),t)=8*x(t)],singsol=all)
 

\begin{align*} x \left (t \right ) &= c_{1} \sin \left (4 t \right )+c_{2} \cos \left (4 t \right ) \\ y \left (t \right ) &= -2 c_{1} \cos \left (4 t \right )+2 c_{2} \sin \left (4 t \right ) \\ \end{align*}

Solution by Mathematica

Time used: 0.005 (sec). Leaf size: 42

DSolve[{x'[t]==-2*y[t],y'[t]==8*x[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
                                                                                    
                                                                                    
 

\begin{align*} x(t)\to c_1 \cos (4 t)-\frac {1}{2} c_2 \sin (4 t) \\ y(t)\to c_2 \cos (4 t)+2 c_1 \sin (4 t) \\ \end{align*}