Internal problem ID [12746]
Book: DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th
edition. Brooks/Cole. Boston, USA. 2012
Section: Chapter 3. Linear Systems. Exercises section 3.1. page 258
Problem number: 6.
ODE order: 1.
ODE degree: 1.
Solve \begin {align*} x^{\prime }\left (t \right )&=3 y\\ y^{\prime }&=3 \pi y-\frac {x \left (t \right )}{3} \end {align*}
✓ Solution by Maple
Time used: 0.031 (sec). Leaf size: 148
dsolve([diff(x(t),t)=3*y(t),diff(y(t),t)=3*Pi*y(t)-1/3*x(t)],[x(t), y(t)], singsol=all)
\begin{align*} x \left (t \right ) = \frac {3 c_{1} {\mathrm e}^{-\frac {\left (-3 \pi +\sqrt {9 \pi ^{2}-4}\right ) t}{2}} \sqrt {9 \pi ^{2}-4}}{2}+\frac {9 c_{1} {\mathrm e}^{-\frac {\left (-3 \pi +\sqrt {9 \pi ^{2}-4}\right ) t}{2}} \pi }{2}-\frac {3 c_{2} {\mathrm e}^{\frac {\left (3 \pi +\sqrt {9 \pi ^{2}-4}\right ) t}{2}} \sqrt {9 \pi ^{2}-4}}{2}+\frac {9 c_{2} {\mathrm e}^{\frac {\left (3 \pi +\sqrt {9 \pi ^{2}-4}\right ) t}{2}} \pi }{2} y \left (t \right ) = c_{1} {\mathrm e}^{-\frac {\left (-3 \pi +\sqrt {9 \pi ^{2}-4}\right ) t}{2}}+c_{2} {\mathrm e}^{\frac {\left (3 \pi +\sqrt {9 \pi ^{2}-4}\right ) t}{2}} \end{align*}
✓ Solution by Mathematica
Time used: 0.016 (sec). Leaf size: 233
DSolve[{x'[t]==3*y[t],y'[t]==3*Pi*y[t]-1/3*x[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
\begin{align*} x(t)\to \frac {e^{-\frac {1}{2} \left (\sqrt {9 \pi ^2-4}-3 \pi \right ) t} \left (\sqrt {9 \pi ^2-4} c_1 \left (e^{\sqrt {9 \pi ^2-4} t}+1\right )-3 \pi c_1 \left (e^{\sqrt {9 \pi ^2-4} t}-1\right )+6 c_2 \left (e^{\sqrt {9 \pi ^2-4} t}-1\right )\right )}{2 \sqrt {9 \pi ^2-4}} y(t)\to \frac {e^{-\frac {1}{2} \left (\sqrt {9 \pi ^2-4}-3 \pi \right ) t} \left (3 c_2 \left (3 \pi \left (e^{\sqrt {9 \pi ^2-4} t}-1\right )+\sqrt {9 \pi ^2-4} \left (e^{\sqrt {9 \pi ^2-4} t}+1\right )\right )-2 c_1 \left (e^{\sqrt {9 \pi ^2-4} t}-1\right )\right )}{6 \sqrt {9 \pi ^2-4}} \end{align*}