e=10;l=50; modell:={x'[t]==y[t], y'[t]==-e(x[t]^2-1)y[t]-x[t], x[0]==2, y[0]==0 }; loesung=NDSolve[modell,{x,y},{t,0,l},MaxSteps->3000]; abb=ParametricPlot[{x[t],y[t]}/.loesung,{t,l/2,l},ImageSize->{400,300}, PlotRange->All,PlotPoints->100,AxesLabel->{"x","y"}];