Internal problem ID [5980]
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: 7.
ODE order: 1.
ODE degree: 1.
Solve \begin {align*} x^{\prime }\relax (t )&=x \relax (t )+y \relax (t )-z \relax (t )\\ y^{\prime }\relax (t )&=2 y \relax (t )\\ z^{\prime }\relax (t )&=y \relax (t )-z \relax (t ) \end {align*}
✓ Solution by Maple
Time used: 0.235 (sec). Leaf size: 50
dsolve([diff(x(t),t)=x(t)+y(t)-z(t),diff(y(t),t)=2*y(t),diff(z(t),t)=y(t)-z(t)],[x(t), y(t), z(t)], singsol=all)
\[ x \relax (t ) = 2 c_{2} {\mathrm e}^{2 t}+c_{1} {\mathrm e}^{t}+\frac {c_{3} {\mathrm e}^{-t}}{2} \] \[ y \relax (t ) = 3 c_{2} {\mathrm e}^{2 t} \] \[ z \relax (t ) = c_{2} {\mathrm e}^{2 t}+c_{3} {\mathrm e}^{-t} \]
✓ Solution by Mathematica
Time used: 0.005 (sec). Leaf size: 86
DSolve[{x'[t]==x[t]+y[t]-z[t],y'[t]==2*y[t],z'[t]==y[t]-z[t]},{x[t],y[t],z[t]},t,IncludeSingularSolutions -> True]
\begin{align*} x(t)\to \frac {1}{6} e^{-t} \left (e^{2 t} \left (4 c_2 e^t+6 c_1-3 (c_2+c_3)\right )-c_2+3 c_3\right ) \\ y(t)\to c_2 e^{2 t} \\ z(t)\to \frac {1}{3} e^{-t} \left (c_2 \left (e^{3 t}-1\right )+3 c_3\right ) \\ \end{align*}