# damped pendulum pend.ode dthet/dt = thetp dthetp/dt = -mu*thetp-sin(thet) pe=(1-cos(thet)) ke=.5*(thetp**2) aux P.E.=pe aux K.E.=ke aux T.E.=pe+ke param mu=0.4 @ XP=T, YP=thet, XLO=0.0, XHI=20.0, YLO=-3.2, YHI=3.2 done