Need help creating dummy variables for plotting

Before I get started into the details here is a link to my code -- https://pastebin.com/R7uCcCsF

Essentially what I'm doing is solving a force ODE using the Runge Kutta numerical integration method. In my code I have a vector, r, which is a position vector with initial values 0 such that r = [x,y,z]. Now I'm solving for r in this runge kutta algorithm and would like to plot all 3 components of the position at each point in time (i.e., plot the trajectory and not just the final point). For this I know I need to create a dummy variable(s). I was looking around but am finding it difficult to apply to my particular case.

I know it goes something like that the variable you'd like to plot and say it's force then your dummy variable would look something like dummyf = force(i); but for my r I have r(1) = x, r(2) = y and so on and so r(i) doesn't write out all 3 values of r at time step i, instead it selects the last value of the i-th (where i can only run from 1 to 3) component of r, which is not what I want at all.

I then tried writing dummy variables like x = r(1), y = r(2) and so on inside the for loop and then plotting them afterwards but to no avail. Then I wrote a second set of variables which I called dummyx, dummyy and dummyz which were defined like; dummyx = x(i); I figured since x was recording the value of r(1) at each time step then defining something as x(i) would plot the value of x at each i we iterate through. However this doesn't seem to be the case.. can anyone help me out here?