originally uploaded to french wiki, 12 avril 2006 à 18:42, by Theon, who made these comments:

Summary

Espace des phases pour le pendule simple. Chaque courbe est un arc paramétré ${\displaystyle t\to (\theta (t),{\dot {\theta }}(t))}$, où t est le temps, ${\displaystyle \theta (t)}$ est l'angle que fait à l'instant t le pendule avec la verticale descendante et ${\displaystyle {\dot {\theta }}(t)}$ est la vitesse angulaire, dérivée de ${\displaystyle \theta (t)}$ par rapport à t. ${\displaystyle \theta (t)}$ est en abscisse et ${\displaystyle {\dot {\theta }}(t)}$ en ordonnée. Les flèches indiquent le sens de parcours des arcs paramétrés.

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Licensing

This work has been released into the public domain by its author, Theon, at the English Wikipedia project. This applies worldwide. In case this is not legally possible: Theon grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

• Source : image créée par l'auteur (Theon)