52.9.14 problem 14

Internal problem ID [8392]
Book : DIFFERENTIAL EQUATIONS with Boundary Value Problems. DENNIS G. ZILL, WARREN S. WRIGHT, MICHAEL R. CULLEN. Brooks/Cole. Boston, MA. 2013. 8th edition.
Section : CHAPTER 8 SYSTEMS OF LINEAR FIRST-ORDER DIFFERENTIAL EQUATIONS. EXERCISES 8.1. Page 332
Problem number : 14
Date solved : Sunday, March 30, 2025 at 01:00:39 PM
CAS classification : system_of_ODEs

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

✓ Maple. Time used: 0.113 (sec). Leaf size: 25

ode:=[diff(x(t),t) = 2*x(t)+y(t), diff(y(t),t) = -x(t)]; 
dsolve(ode);
 

\begin{align*} x \left (t \right ) &= -{\mathrm e}^{t} \left (c_2 t +c_1 +c_2 \right ) \\ y \left (t \right ) &= {\mathrm e}^{t} \left (c_2 t +c_1 \right ) \\ \end{align*}

✓ Mathematica. Time used: 0.003 (sec). Leaf size: 38

ode={D[x[t],t]==2*x[t]+y[t],D[y[t],t]==-x[t]}; 
ic={}; 
DSolve[{ode,ic},{x[t],y[t]},t,IncludeSingularSolutions->True]
 

\begin{align*} x(t)\to e^t (c_1 (t+1)+c_2 t) \\ y(t)\to e^t (c_2-(c_1+c_2) t) \\ \end{align*}

✓ Sympy. Time used: 0.083 (sec). Leaf size: 31

from sympy import * 
t = symbols("t") 
x = Function("x") 
y = Function("y") 
ode=[Eq(-2*x(t) - y(t) + Derivative(x(t), t),0),Eq(x(t) + Derivative(y(t), t),0)] 
ics = {} 
dsolve(ode,func=[x(t),y(t)],ics=ics)
 

\[ \left [ x{\left (t \right )} = C_{2} t e^{t} + \left (C_{1} + C_{2}\right ) e^{t}, \ y{\left (t \right )} = - C_{1} e^{t} - C_{2} t e^{t}\right ] \]