5.2 problem Example 3

Internal problem ID [355]

Book: Differential equations and linear algebra, 4th ed., Edwards and Penney
Section: Section 7.6, Multiple Eigenvalue Solutions. Examples. Page 437
Problem number: Example 3.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x_{1}^{\prime }\relax (t )&=x_{1}\relax (t )-3 x_{2}\relax (t )\\ x_{2}^{\prime }\relax (t )&=3 x_{1}\relax (t )+7 x_{2}\relax (t ) \end {align*}

Solution by Maple

Time used: 0.013 (sec). Leaf size: 35

dsolve([diff(x__1(t),t)=1*x__1(t)-3*x__2(t),diff(x__2(t),t)=3*x__1(t)+7*x__2(t)],[x__1(t), x__2(t)], singsol=all)
 

\[ x_{1}\relax (t ) = -\frac {{\mathrm e}^{4 t} \left (3 c_{2} t +3 c_{1}-c_{2}\right )}{3} \] \[ x_{2}\relax (t ) = {\mathrm e}^{4 t} \left (c_{2} t +c_{1}\right ) \]

Solution by Mathematica

Time used: 0.003 (sec). Leaf size: 44

DSolve[{x1'[t]==1*x1[t]-3*x2[t],x2'[t]==3*x1[t]+7*x2[t]},{x1[t],x2[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} \text {x1}(t)\to e^{4 t} (-3 c_1 t-3 c_2 t+c_1) \\ \text {x2}(t)\to e^{4 t} (3 (c_1+c_2) t+c_2) \\ \end{align*}