No worries; I found a nice tutorial on how to do it in matlab, and adapted it for my own purposes.
If anyone has a similar problem, see this youtube video, it's very good:
https://www.youtube.com/watch?v=http://www.youtube.com/watch?v=fx3bl4oA_0U
Homework Statement
I have a second-order non-linear differential equation that I am trying to solve. So far I have decomposed it into a system of 2 first-order equations, and have (possibly) determined that it cannot be solved analytically. So I am trying to do a nice numerical approximation...