18.6 problem 6

Internal problem ID [783]

Book: Elementary differential equations and boundary value problems, 10th ed., Boyce and DiPrima
Section: Chapter 7.9, Nonhomogeneous Linear Systems. page 447
Problem number: 6.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x_{1}^{\prime }\left (t \right )&=-4 x_{1} \left (t \right )+2 x_{2} \left (t \right )+\frac {1}{t}\\ x_{2}^{\prime }\left (t \right )&=2 x_{1} \left (t \right )-x_{2} \left (t \right )+\frac {2}{t}+4 \end {align*}

Solution by Maple

Time used: 0.031 (sec). Leaf size: 45

dsolve([diff(x__1(t),t)=-4*x__1(t)+2*x__2(t)+1/t,diff(x__2(t),t)=2*x__1(t)-1*x__2(t)+2/t+4],singsol=all)
 

\begin{align*} x_{1} \left (t \right ) &= \ln \left (-5 t \right )-\frac {c_{1} {\mathrm e}^{-5 t}}{5}+\frac {8 t}{5}+c_{2} \\ x_{2} \left (t \right ) &= \frac {c_{1} {\mathrm e}^{-5 t}}{10}+2 \ln \left (-5 t \right )+2 c_{2} +\frac {16 t}{5}+\frac {4}{5} \\ \end{align*}

Solution by Mathematica

Time used: 0.02 (sec). Leaf size: 86

DSolve[{x1'[t]==-4*x1[t]+2*x2[t]+1/t,x2'[t]==2*x1[t]-1*x2[t]+2/t+4},{x1[t],x2[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} \text {x1}(t)\to \frac {1}{25} \left (40 t+25 \log (t)+20 c_1 e^{-5 t}-10 c_2 e^{-5 t}-8+5 c_1+10 c_2\right ) \\ \text {x2}(t)\to \frac {1}{25} \left (80 t+50 \log (t)-10 c_1 e^{-5 t}+5 c_2 e^{-5 t}+4+10 c_1+20 c_2\right ) \\ \end{align*}