72.10.1 problem 1

Internal problem ID [14733]
Book : DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th edition. Brooks/Cole. Boston, USA. 2012
Section : Chapter 3. Linear Systems. Exercises section 3.2. page 277
Problem number : 1
Date solved : Thursday, March 13, 2025 at 04:17:54 AM
CAS classification : system_of_ODEs

\begin{align*} \frac {d}{d t}x \left (t \right )&=3 x \left (t \right )\\ \frac {d}{d t}y \left (t \right )&=-2 y \left (t \right ) \end{align*}

✓ Maple. Time used: 0.033 (sec). Leaf size: 19

ode:=[diff(x(t),t) = 3*x(t), diff(y(t),t) = -2*y(t)]; 
dsolve(ode);
 

\begin{align*} x \left (t \right ) &= c_{2} {\mathrm e}^{3 t} \\ y &= c_{1} {\mathrm e}^{-2 t} \\ \end{align*}

✓ Mathematica. Time used: 0.002 (sec). Leaf size: 32

ode={D[x[t],t]==3*x[t],D[y[t],t]==-2*x[t]}; 
ic={}; 
DSolve[{ode,ic},{x[t],y[t]},t,IncludeSingularSolutions->True]
 

\begin{align*} x(t)\to c_1 e^{3 t} \\ y(t)\to c_2-\frac {2}{3} c_1 \left (e^{3 t}-1\right ) \\ \end{align*}

✓ Sympy. Time used: 0.070 (sec). Leaf size: 17

from sympy import * 
t = symbols("t") 
x = Function("x") 
y = Function("y") 
ode=[Eq(-3*x(t) + Derivative(x(t), t),0),Eq(2*y(t) + Derivative(y(t), t),0)] 
ics = {} 
dsolve(ode,func=[x(t),y(t)],ics=ics)
 

\[ \left [ x{\left (t \right )} = C_{1} e^{3 t}, \ y{\left (t \right )} = C_{2} e^{- 2 t}\right ] \]