9.9 problem 9

Internal problem ID [12749]

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: 9.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x^{\prime }\left (t \right )&=\beta y\\ y^{\prime }&=\gamma x \left (t \right )-y \end {align*}

Solution by Maple

Time used: 0.032 (sec). Leaf size: 128

dsolve([diff(x(t),t)=beta*y(t),diff(y(t),t)=gamma*x(t)-y(t)],[x(t), y(t)], singsol=all)
 

\begin{align*} x \left (t \right ) = \frac {c_{1} {\mathrm e}^{\frac {\left (-1+\sqrt {4 \gamma \beta +1}\right ) t}{2}} \sqrt {4 \gamma \beta +1}-c_{2} {\mathrm e}^{-\frac {\left (1+\sqrt {4 \gamma \beta +1}\right ) t}{2}} \sqrt {4 \gamma \beta +1}+c_{1} {\mathrm e}^{\frac {\left (-1+\sqrt {4 \gamma \beta +1}\right ) t}{2}}+c_{2} {\mathrm e}^{-\frac {\left (1+\sqrt {4 \gamma \beta +1}\right ) t}{2}}}{2 \gamma } y \left (t \right ) = c_{1} {\mathrm e}^{\frac {\left (-1+\sqrt {4 \gamma \beta +1}\right ) t}{2}}+c_{2} {\mathrm e}^{-\frac {\left (1+\sqrt {4 \gamma \beta +1}\right ) t}{2}} \end{align*}

Solution by Mathematica

Time used: 0.019 (sec). Leaf size: 202

DSolve[{x'[t]==\[Beta]*y[t],y'[t]==\[Gamma]*x[t]-y[t]},{x[t],y[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} x(t)\to \frac {e^{-\frac {1}{2} t \left (\sqrt {4 \beta \gamma +1}+1\right )} \left (c_1 \left (\sqrt {4 \beta \gamma +1}+\left (\sqrt {4 \beta \gamma +1}+1\right ) e^{t \sqrt {4 \beta \gamma +1}}-1\right )+2 \beta c_2 \left (e^{t \sqrt {4 \beta \gamma +1}}-1\right )\right )}{2 \sqrt {4 \beta \gamma +1}} y(t)\to \frac {e^{-\frac {1}{2} t \left (\sqrt {4 \beta \gamma +1}+1\right )} \left (2 \gamma c_1 \left (e^{t \sqrt {4 \beta \gamma +1}}-1\right )+c_2 \left (\sqrt {4 \beta \gamma +1}+\left (\sqrt {4 \beta \gamma +1}-1\right ) e^{t \sqrt {4 \beta \gamma +1}}+1\right )\right )}{2 \sqrt {4 \beta \gamma +1}} \end{align*}