Physics Help Forum Pendulum

 Mar 3rd 2010, 03:47 PM #1 Junior Member   Join Date: Dec 2009 Posts: 5 Pendulum Rather than solve the double pendulum problem with two masses in the usual way. Instead express the coordinates of the second mass, in terms of the coordinates of the mass above it. $\displaystyle$ x2=x_1+\xi = L_1Sin[\theta]Cos[\phi]+L_2Sin[\alpha]Cos[\beta]$\\$ y2=y_1+ \eta = L_1Sin[\theta]Sin[\phi]+L_2Sin[\alpha]Sin[\beta]$\\$ z2=z_1-\xi = L_1-L_1Cos[\theta]-L_2Sin[\alpha]Cos[\beta] Wouldn't you suspect that the Lagrangian remain invariant? Is there a way to reparameterize these equations? Attached Thumbnails