19.13 problem 13

Internal problem ID [804]

Book: Elementary differential equations and boundary value problems, 10th ed., Boyce and DiPrima
Section: Chapter 9.1, The Phase Plane: Linear Systems. page 505
Problem number: 13.
ODE order: 1.
ODE degree: 1.

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

Solution by Maple

Time used: 0.031 (sec). Leaf size: 70

dsolve([diff(x__1(t),t)=1*x__1(t)+1*x__2(t)-2,diff(x__2(t),t)=1*x__1(t)-1*x__2(t)],[x__1(t), x__2(t)], singsol=all)
 

\[ x_{1} \left (t \right ) = \sqrt {2}\, {\mathrm e}^{t \sqrt {2}} c_{2} -\sqrt {2}\, {\mathrm e}^{-t \sqrt {2}} c_{1} +{\mathrm e}^{t \sqrt {2}} c_{2} +{\mathrm e}^{-t \sqrt {2}} c_{1} +1 \] \[ x_{2} \left (t \right ) = {\mathrm e}^{t \sqrt {2}} c_{2} +{\mathrm e}^{-t \sqrt {2}} c_{1} +1 \]

Solution by Mathematica

Time used: 0.103 (sec). Leaf size: 74

DSolve[{x1'[t]==1*x1[t]+1*x2[t]-2,x2'[t]==1*x1[t]-1*x2[t]},{x1[t],x2[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} \text {x1}(t)\to c_1 \cosh \left (\sqrt {2} t\right )+\frac {(c_1+c_2) \sinh \left (\sqrt {2} t\right )}{\sqrt {2}}+1 \\ \text {x2}(t)\to c_2 \cosh \left (\sqrt {2} t\right )+\frac {(c_1-c_2) \sinh \left (\sqrt {2} t\right )}{\sqrt {2}}+1 \\ \end{align*}