How to use comet to trace the path of an object?

I am writing a code for the simulation of double pendulum and i need to trace the path of the bob. But I am having trouble with it. This is a part of my code. Basically,i am having trouble in this portion. Though I use the command comet,it doesn't trace the path. Anyone who could point out my mistake and help me solve the problem? Here x1(i),y1(i) is the poition of first bob.

 for i = 1 : max(arraysize)
      plotarrayy = [pendulumtopy y1(i)];  % Plots solution at each time interval
    plotarrayx = [pendulumtopx x1(i)];
    plotarray2x = [x1(i) x2(i)];
    plotarray2y = [y1(i) y2(i)];
      plot(x1(i),y1(i),'ro',x2(i),y2(i),'bo','markersize',5,'markerfacecolor','r')
         hold on
      comet(y1(i));

Answer 1

[jonatan]

comet requires the input(s) to be a vector and not a single value, as you wrote. In order to use this function, you should run it after the for loop:

comet(x1,y1)

[reema shrestha]

What should be the input for the comet outside the loop? I tried using

 comet(y(i))

But then i only runs inside loop,isn't it??

[Image Analyst]

Outside the loop, it should be what he said it should be:

comet(x1,y1)

Why did you change it?