9.49 problem 1904

Internal problem ID [9479]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 8, system of first order odes
Problem number: 1904.
ODE order: 1.
ODE degree: 1.

Solve \begin {align*} x^{\prime }\left (t \right )&=c y \left (t \right )-b z \left (t \right )\\ y^{\prime }\left (t \right )&=a z \left (t \right )-c x \left (t \right )\\ z^{\prime }\left (t \right )&=b x \left (t \right )-a y \left (t \right ) \end {align*}

Solution by Maple

Time used: 0.078 (sec). Leaf size: 312

dsolve([diff(x(t),t)=c*y(t)-b*z(t),diff(y(t),t)=a*z(t)-c*x(t),diff(z(t),t)=b*x(t)-a*y(t)],[x(t), y(t), z(t)], singsol=all)
 

\[ x \left (t \right ) = -\frac {\sin \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) \sqrt {a^{2}+b^{2}+c^{2}}\, c_{3} b c +\sin \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) c_{2} a \,c^{2}-\cos \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) \sqrt {a^{2}+b^{2}+c^{2}}\, c_{2} b c +\cos \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) c_{3} a \,c^{2}-c_{1} a^{3}-c_{1} a \,b^{2}}{c \left (a^{2}+b^{2}\right )} \] \[ y \left (t \right ) = \frac {\sin \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) \sqrt {a^{2}+b^{2}+c^{2}}\, c_{3} a c -\sin \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) c_{2} b \,c^{2}-\cos \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) \sqrt {a^{2}+b^{2}+c^{2}}\, c_{2} a c -\cos \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) c_{3} b \,c^{2}+a^{2} b c_{1} +c_{1} b^{3}}{c \left (a^{2}+b^{2}\right )} \] \[ z \left (t \right ) = c_{1} +c_{2} \sin \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right )+c_{3} \cos \left (\sqrt {a^{2}+b^{2}+c^{2}}\, t \right ) \]

Solution by Mathematica

Time used: 0.029 (sec). Leaf size: 405

DSolve[{x'[t]==c*y[t]-b*z[t],y'[t]==a*z[t]-c*x[t],z'[t]==b*x[t]-a*y[t]},{x[t],y[t],z[t]},t,IncludeSingularSolutions -> True]
 

\begin{align*} x(t)\to \frac {\left (-a b c_2+c (c c_1-a c_3)+b^2 c_1\right ) \cosh \left (t \sqrt {-a^2-b^2-c^2}\right )+\sqrt {-a^2-b^2-c^2} (b c_3-c c_2) \sinh \left (t \sqrt {-a^2-b^2-c^2}\right )+a (a c_1+b c_2+c c_3)}{a^2+b^2+c^2} \\ y(t)\to \frac {\left (a^2 c_2-a b c_1+c (c c_2-b c_3)\right ) \cosh \left (t \sqrt {-a^2-b^2-c^2}\right )+\sqrt {-a^2-b^2-c^2} (c c_1-a c_3) \sinh \left (t \sqrt {-a^2-b^2-c^2}\right )+b (a c_1+b c_2+c c_3)}{a^2+b^2+c^2} \\ z(t)\to \frac {\left (c_3 \left (a^2+b^2\right )-c (a c_1+b c_2)\right ) \cosh \left (t \sqrt {-a^2-b^2-c^2}\right )+\sqrt {-a^2-b^2-c^2} (a c_2-b c_1) \sinh \left (t \sqrt {-a^2-b^2-c^2}\right )+c (a c_1+b c_2+c c_3)}{a^2+b^2+c^2} \\ \end{align*}