76.29.1 problem 1

Internal problem ID [17877]
Book : Differential equations. An introduction to modern methods and applications. James Brannan, William E. Boyce. Third edition. Wiley 2015
Section : Chapter 6. Systems of First Order Linear Equations. Section 6.7 (Defective Matrices). Problems at page 444
Problem number : 1
Date solved : Tuesday, January 28, 2025 at 11:09:36 AM
CAS classification : system_of_ODEs

\begin{align*} \frac {d}{d t}x_{1} \left (t \right )&=4 x_{1} \left (t \right )-9 x_{2} \left (t \right )\\ \frac {d}{d t}x_{2} \left (t \right )&=x_{1} \left (t \right )-2 x_{2} \left (t \right ) \end{align*}

✓ Solution by Maple

Time used: 0.040 (sec). Leaf size: 30

dsolve([diff(x__1(t),t)=4*x__1(t)-9*x__2(t),diff(x__2(t),t)=1*x__1(t)-2*x__2(t)],singsol=all)
 

\begin{align*} x_{1} \left (t \right ) &= {\mathrm e}^{t} \left (c_{2} t +c_{1} \right ) \\ x_{2} \left (t \right ) &= \frac {{\mathrm e}^{t} \left (3 c_{2} t +3 c_{1} -c_{2} \right )}{9} \\ \end{align*}

✓ Solution by Mathematica

Time used: 0.002 (sec). Leaf size: 41

DSolve[{D[x1[t],t]==4*x1[t]-9*x2[t],D[x2[t],t]==1*x1[t]-2*x2[t]},{x1[t],x2[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} \text {x1}(t)\to e^t (3 c_1 t-9 c_2 t+c_1) \\ \text {x2}(t)\to e^t ((c_1-3 c_2) t+c_2) \\ \end{align*}