22.19 problem section 10.5, problem 19

Internal problem ID [1622]

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 19.
ODE order: 1.
ODE degree: 1.

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

With initial conditions \[ [y_{1} \left (0\right ) = -6, y_{2} \left (0\right ) = -2, y_{3} \left (0\right ) = 0] \]

Solution by Maple

Time used: 0.016 (sec). Leaf size: 41

dsolve([diff(y__1(t),t) = -2*y__1(t)+2*y__2(t)+y__3(t), diff(y__2(t),t) = -2*y__1(t)+2*y__2(t)+y__3(t), diff(y__3(t),t) = -3*y__1(t)+3*y__2(t)+2*y__3(t), y__1(0) = -6, y__2(0) = -2, y__3(0) = 0], singsol=all)
 

\begin{align*} y_{1} \left (t \right ) &= -9+2 t +3 \,{\mathrm e}^{2 t} \\ y_{2} \left (t \right ) &= 3 \,{\mathrm e}^{2 t}-5+2 t \\ y_{3} \left (t \right ) &= -6+6 \,{\mathrm e}^{2 t} \\ \end{align*}

Solution by Mathematica

Time used: 0.006 (sec). Leaf size: 44

DSolve[{y1'[t]==-2*y1[t]+2*y2[t]+1*y3[t],y2'[t]==-2*y1[t]+2*y2[t]+1*y3[t],y3'[t]==-3*y1[t]+3*y2[t]+2*y3[t]},{y1[0]==-6,y2[0]==-2,y3[0]==0},{y1[t],y2[t],y3[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} \text {y1}(t)\to 2 t+3 e^{2 t}-9 \\ \text {y2}(t)\to 2 t+3 e^{2 t}-5 \\ \text {y3}(t)\to 6 \left (e^{2 t}-1\right ) \\ \end{align*}