Internal problem ID [5982]
Book: DIFFERENTIAL EQUATIONS with Boundary Value Problems. DENNIS G. ZILL,
WARREN S. WRIGHT, MICHAEL R. CULLEN. Brooks/Cole. Boston, MA. 2013. 8th
edition.
Section: CHAPTER 8 SYSTEMS OF LINEAR FIRST-ORDER DIFFERENTIAL EQUATIONS.
EXERCISES 8.2. Page 346
Problem number: 9.
ODE order: 1.
ODE degree: 1.
Solve \begin {align*} x^{\prime }\relax (t )&=-x \relax (t )+y \relax (t )\\ y^{\prime }\relax (t )&=x \relax (t )+2 y \relax (t )+z \relax (t )\\ z^{\prime }\relax (t )&=3 y \relax (t )-z \relax (t ) \end {align*}
✓ Solution by Maple
Time used: 0.172 (sec). Leaf size: 67
dsolve([diff(x(t),t)=-x(t)+y(t),diff(y(t),t)=x(t)+2*y(t)+z(t),diff(z(t),t)=3*y(t)-z(t)],[x(t), y(t), z(t)], singsol=all)
\[ x \relax (t ) = -c_{1} {\mathrm e}^{-t}+\frac {{\mathrm e}^{3 t} c_{2}}{3}+\frac {c_{3} {\mathrm e}^{-2 t}}{3} \] \[ y \relax (t ) = \frac {4 \,{\mathrm e}^{3 t} c_{2}}{3}-\frac {c_{3} {\mathrm e}^{-2 t}}{3} \] \[ z \relax (t ) = c_{1} {\mathrm e}^{-t}+{\mathrm e}^{3 t} c_{2}+c_{3} {\mathrm e}^{-2 t} \]
✓ Solution by Mathematica
Time used: 0.015 (sec). Leaf size: 147
DSolve[{x'[t]==-x[t]+y[t],y'[t]==x[t]+2*y[t]+z[t],z'[t]==3*y[t]-z[t]},{x[t],y[t],z[t]},t,IncludeSingularSolutions -> True]
\begin{align*} x(t)\to \frac {1}{20} e^{-2 t} \left (5 (3 c_1-c_3) e^t+(c_1+4 c_2+c_3) e^{5 t}+4 (c_1-c_2+c_3)\right ) \\ y(t)\to \frac {1}{5} e^{-2 t} \left ((c_1+4 c_2+c_3) e^{5 t}-c_1+c_2-c_3\right ) \\ z(t)\to \frac {1}{20} e^{-2 t} \left (-5 (3 c_1-c_3) e^t+3 (c_1+4 c_2+c_3) e^{5 t}+12 (c_1-c_2+c_3)\right ) \\ \end{align*}