# gedempte slinger
from sage.calculus.desolvers import desolve_odeint
x,y,t=var('x,y,t')
mu=1 # slinger is gedempt als mu>0
f=[y,-mu*y-sin(x)]
p1=plot_vector_field(f,(x,-1.5,1.5),(y,-1.5,1.5))
sol=desolve_odeint(f,[0.1,0.1],srange(0,50,0.1),[x,y])
p2=line(zip(sol[:,0],sol[:,1]),color='blue')
sol=desolve_odeint(f,[0.5,0.5],srange(0,50,0.1),[x,y])
p3=line(zip(sol[:,0],sol[:,1]),color='magenta')
sol=desolve_odeint(f,[0.8,0.8],srange(0,50,0.1),[x,y])
p4=line(zip(sol[:,0],sol[:,1]),color='red')
p=p1+p2+p3+p4
show(p)
