function phasemovie
    clear;clf;
    A=[-5, 1; -18, 1];
    [a,b]=solve('-y+1=0','4*x-8=0');
    a=double(a);
    b=double(b);
    tmax=10;
    [x0,y0]=ginput(1);
    [T,Z]=ode45(@ff,[0,tmax],[x0,y0]);
    [T1,Z1]=ode45(@ff,[0,-tmax],[x0,y0]);
    axis([a-5,a+5,b-5,b+5])
    A1=Z1(:,1);B1=Z1(:,2);
    A2=A1(length(A1):-1:2);
    B2=B1(length(B1):-1:2);
    A3=[A2;Z(:,1)];
    B=[B2;Z(:,2)];
    x=[];y=[];
    for k=1:length(A3)
        x=[x,A3(k)];
        y=[y,B(k)];
        plot(x,y)
        axis([a-200,a+200,b-200,b+200])
        M(k)=getframe;
    end
    Movie(M,2)
    function z=ff(t,y)
        z=A*y;
        
    end
      

end

