I'm probably going to learn about the double pendulum in a few weeks, however I have a question that I can't get rid off from my head. Is there a time (I imagine it to be very large) where the pendulum reach the initial position/configuration? In another words, a time where it moves as it has moved. Maybe we can call this a period, but I'm not really sure. If I remember well, Poincaré's recurrence theorem implies the existence of such a time. Mathematically I must have the motion equation under my eyes and set [tex]t=0[/tex]. I do the same but setting [tex]t=t_1[/tex]. And lastly I equal both equation and I solve for [tex]t_1[/tex]. I'm guessing it's very hard to solve for [tex]t_1[/tex] since I never heard of a period of a double pendulum. Do someone has something to say?