Internal problem ID [385]
Book: Differential equations and linear algebra, 4th ed., Edwards and Penney
Section: Section 7.6, Multiple Eigenvalue Solutions. Page 451
Problem number: problem 28.
ODE order: 1.
ODE degree: 1.
Solve \begin {align*} x_{1}^{\prime }\left (t \right )&=-15 x_{1} \left (t \right )-7 x_{2} \left (t \right )+4 x_{3} \left (t \right )\\ x_{2}^{\prime }\left (t \right )&=34 x_{1} \left (t \right )+16 x_{2} \left (t \right )-11 x_{3} \left (t \right )\\ x_{3}^{\prime }\left (t \right )&=17 x_{1} \left (t \right )+7 x_{2} \left (t \right )+5 x_{3} \left (t \right ) \end {align*}
✓ Solution by Maple
Time used: 0.031 (sec). Leaf size: 73
dsolve([diff(x__1(t),t)=-15*x__1(t)-7*x__2(t)+4*x__3(t),diff(x__2(t),t)=34*x__1(t)+16*x__2(t)-11*x__3(t),diff(x__3(t),t)=17*x__1(t)+7*x__2(t)+5*x__3(t)],singsol=all)
\begin{align*} x_{1} \left (t \right ) &= {\mathrm e}^{2 t} \left (c_{3} t^{2}+c_{2} t +c_{1} \right ) \\ x_{2} \left (t \right ) &= -\frac {{\mathrm e}^{2 t} \left (833 c_{3} t^{2}+833 c_{2} t +42 c_{3} t +833 c_{1} +21 c_{2} -8 c_{3} \right )}{343} \\ x_{3} \left (t \right ) &= \frac {{\mathrm e}^{2 t} \left (14 c_{3} t +7 c_{2} +2 c_{3} \right )}{49} \\ \end{align*}
✓ Solution by Mathematica
Time used: 0.007 (sec). Leaf size: 124
DSolve[{x1'[t]==-15*x1[t]-7*x2[t]+4*x3[t],x2'[t]==34*x1[t]+16*x2[t]-11*x3[t],x3'[t]==17*x1[t]+7*x2[t]+5*x3[t]},{x1[t],x2[t],x3[t]},t,IncludeSingularSolutions -> True]
\begin{align*} \text {x1}(t)\to \frac {1}{2} e^{2 t} \left (c_1 \left (119 t^2-34 t+2\right )+7 c_2 t (7 t-2)+c_3 t (21 t+8)\right ) \\ \text {x2}(t)\to -\frac {1}{2} e^{2 t} \left (17 (17 c_1+7 c_2+3 c_3) t^2+(-68 c_1-28 c_2+22 c_3) t-2 c_2\right ) \\ \text {x3}(t)\to e^{2 t} ((17 c_1+7 c_2+3 c_3) t+c_3) \\ \end{align*}