64.24.5 problem 5

Internal problem ID [13690]
Book : Differential Equations by Shepley L. Ross. Third edition. John Willey. New Delhi. 2004.
Section : Chapter 13, Nonlinear differential equations. Section 13.2, Exercises page 656
Problem number : 5
Date solved : Tuesday, January 28, 2025 at 05:55:18 AM
CAS classification : system_of_ODEs

\begin{align*} \frac {d}{d t}x \left (t \right )&=2 x \left (t \right )-4 y \left (t \right )\\ \frac {d}{d t}y \left (t \right )&=2 x \left (t \right )-2 y \left (t \right ) \end{align*}

Solution by Maple

Time used: 0.034 (sec). Leaf size: 49

dsolve([diff(x(t),t)=2*x(t)-4*y(t),diff(y(t),t)=2*x(t)-2*y(t)],singsol=all)
 
\begin{align*} x \left (t \right ) &= c_{1} \sin \left (2 t \right )+c_{2} \cos \left (2 t \right ) \\ y \left (t \right ) &= -\frac {\cos \left (2 t \right ) c_{1}}{2}+\frac {\sin \left (2 t \right ) c_{2}}{2}+\frac {c_{1} \sin \left (2 t \right )}{2}+\frac {c_{2} \cos \left (2 t \right )}{2} \\ \end{align*}

Solution by Mathematica

Time used: 0.010 (sec). Leaf size: 48

DSolve[{D[x[t],t]==2*x[t]-4*y[t],D[y[t],t]==2*x[t]-2*y[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
 
\begin{align*} x(t)\to c_1 \cos (2 t)+(c_1-2 c_2) \sin (2 t) \\ y(t)\to c_2 \cos (2 t)+(c_1-c_2) \sin (2 t) \\ \end{align*}