22.10 problem section 10.5, problem 10

Internal problem ID [1613]

Book: Elementary differential equations with boundary value problems. William F. Trench. Brooks/Cole 2001
Section: Chapter 10 Linear system of Differential equations. Section 10.5, constant coefficient homogeneous system II. Page 555
Problem number: section 10.5, problem 10.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} y_{1}^{\prime }\left (t \right )&=-y_{1} \left (t \right )+y_{2} \left (t \right )-y_{3} \left (t \right )\\ y_{2}^{\prime }\left (t \right )&=-2 y_{1} \left (t \right )+2 y_{3} \left (t \right )\\ y_{3}^{\prime }\left (t \right )&=-y_{1} \left (t \right )+3 y_{2} \left (t \right )-y_{3} \left (t \right ) \end {align*}

Solution by Maple

Time used: 0.032 (sec). Leaf size: 63

dsolve([diff(y__1(t),t)=-1*y__1(t)+1*y__2(t)-1*y__3(t),diff(y__2(t),t)=-2*y__1(t)+0*y__2(t)+2*y__3(t),diff(y__3(t),t)=-1*y__1(t)+3*y__2(t)-1*y__3(t)],singsol=all)
 

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

Solution by Mathematica

Time used: 0.007 (sec). Leaf size: 125

DSolve[{y1'[t]==-1*y1[t]+1*y2[t]-1*y3[t],y2'[t]==-2*y1[t]+0*y2[t]+2*y3[t],y3'[t]==-1*y1[t]+3*y2[t]-1*y3[t]},{y1[t],y2[t],y3[t]},t,IncludeSingularSolutions -> True]
                                                                                    
                                                                                    
 

\begin{align*} \text {y1}(t)\to e^{-2 t} (c_1 (t+1)+(c_2-c_3) t) \\ \text {y2}(t)\to \frac {1}{2} e^{-2 t} \left (-\left (c_1 \left (e^{4 t}-1\right )\right )+c_2 \left (e^{4 t}+1\right )+c_3 \left (e^{4 t}-1\right )\right ) \\ \text {y3}(t)\to \frac {1}{2} e^{-2 t} \left (c_1 \left (2 t-e^{4 t}+1\right )+c_2 \left (2 t+e^{4 t}-1\right )+c_3 \left (-2 t+e^{4 t}+1\right )\right ) \\ \end{align*}